And in case you are wondering what I mean by "hyper productive" (and I apologise if this is not the original meaning, but I think it is...): it means being able to go faster as time progresses. On normal projects it is easiest to work on the project when it is still greenfield -- you have no constraints to work around. As you work on the project, the decisions you make create constraints and make it more difficult to change what it does.
With a hyper productive team it works the other way around. Imagine working on an embedded system where you may have a compiler, but you have no standard libraries, or frameworks or third party code to help you. It's very slow because you have to build all of the tools that you need to go forward. You have to consider all of the abstractions and build designs that make it easy to follow those abstractions. On modern systems we have lots of tools that allow our "green field" projects to be boot strapped quickly. Now imagine that you are constantly keeping your code in a state where every future change is like that. As the code base gains capability, it actually makes it easier to make the next thing. This, of course, is the holy grail of programming :-) You can make a lot of money selling maps to the holy grail, so you shouldn't believe me!
With that disclaimer, I will rashly state that I have been on "hyper productive" projects before. But it's a pretty ridiculous tightrope. For anything I could say, there will be someone who will reply, "Yes, that sounds great in theory, but what if X happens? It will all come crashing down". Those people are correct. That's why XP is not the 12 practices. They are just something that will hopefully make you aware of what you need to do when X happens.
I don't think XP is the only way to get to "hyper productive", but it is they way I have used to get there. I don't know any other way, personally, but that doesn't mean that it doesn't exist. Usually when people ask me the question you have asked, I direct them to XP and suggest that they study it thoroughly (including running projects in full-on XP mode). The problem is the "Agile" attitude that people usually bring with them. Because they think, "Well, that doesn't make sense", or "I can't do that because Y" and they use their experience to insert something else. In the end they create a kind of "We tried baseball and it didn't work" situation (to borrow from Ron Jeffries again). It's a catch 22. Blindly applying the XP practices won't give you success, but you probably can't get the experience to understand where the practices are pointing without doing just that.
Even for me, where I've had success with those techniques, I often find myself in situations where I can't actually get there from here. So I try things I haven't tried before (usually without success :-) ). Or I wait until the situation changes and I can get there from here. It's really hard.
I'd love to talk more about politics and the difficulty of just getting people to walk in the same direction. For example, I often tell the story about 5 people all walking in different directions. One of the people is walking in the right direction, but every one of them thinks they are walking in the right direction, so they can't agree. Let's take the position of the person walking in the right direction. If that person just pushes on, then they will arrive safely, but the 4 other team members will fail -- and hence the project will fail. So it makes more sense for everyone to walk together even if it is in the wrong direction, because you have a chance that you can change course and succeed. If everyone goes in different directions, then you will fail, almost by definition -- even though one of them might be right.
The problem about talking about things like the above is that I don't fully understand what to do. Kent Beck's famous C3 project was a technical success (though, I'm not sure it was every fully implemented) because all of the team members were fed up with the previous process and were willing to do pretty much anything else. My most successful project was actually similar -- the previous manager had been overbearing and couldn't work with the team members. He was removed from the project and I was inserted "to make everyone happy". So I did -- they wanted to try "this XP thing" and my job was to make them happy. (Side note: you usually don't go far wrong if you make your workers happy).
But there is far more to it than that. I always say that the most dangerous actors in a project are senior management. Virtually every failed project I have been on (and I've been on a lot) has failed because it was cancelled by senior management. Now, I say that partially tongue in cheek because projects don't fail until they stop and they don't stop until they are cancelled :-). But it's actually true in a very real fashion. Most poor choices actually stem from trying to appease stake holders or managers who are worried about something. Again, I will say that XP can really help you there, but I will forgive you if you look at the 12 practices and say, "I don't see how".
I didn't really intend to write a long response to this question, but... you can see what happened. It's really a difficult question to answer and I'm not sure that my answer sheds any light. However, just keep pressing on. The holy grail is there. I've seen it. Your path will be different than mine, but you can get there if you keep believing.
My understanding is that C3 was a failure in every respect (except in terms of the results on the careers of certain evangelists). So I'm curious what you mean when you say "a technical success".
It's hard to talk about this kind of stuff for reasons like you bring up. As you say, XP and the mythos surrounding it brought many people to the public eye that might not have been so noticeable. Although having lived through that time, Kent Beck and Ward Cunningham were pretty big names in the OO community even before XP. In fact, I doubt that anybody would have looked at XP (given that it is so strange) if someone lesser known had been behind it.
I struggle with this quite a bit. I've been lucky enough to meet and even work with some of the big names in the London tech scene. I mean, people are people and they sometimes have some pretty stupid ideas. They sometimes do some stupid things that don't work well. They sometimes don't realise which of their ideas are stupid :-) But without exception, they've been really awesome to talk to, work with and learn from.
I think C3 suffers a bit from the perspective of being "the example", even though it's clear that it wasn't all positive. I tend to look at it as the point at which the people involved realised, "Hey, this could work." When you decide to write a book about this kind of stuff, on one side you are being a good self-promoter, but on the other side you are really putting yourself out there. Is there some defensiveness there? I wouldn't doubt it.
My view has been to try to ignore the people behind the ideas. A lot of time you have to think to yourself, "How do I evaluate this idea? There are so many ideas. Which ones should I consider and which ones should I let go?". Unlike Pokemon, I think the secret is that you don't have to catch them all. Although there are many paths out there, my personal feeling is that there are probably not that many destinations. We'll all converge eventually. So follow the path that looks interesting to you.
XP is the path that took me the farthest so far. It's hard to give people advice because I can say, "I know XP can take you here, because I did it that way". I don't know any other way so far, so I can't give good advice on other good paths (although I can give a lot of advice about bad paths -- as I'm sure all experienced developers can relate to :-) ).
Hope that answers the question!