And weird that nobody suggested the Bitcoin block chain. I don't think binaries are a good fit but source code doesn't require a lot of space. With the current and future block size it will take sometime to make it happen.
Archive.org (while an amazing resource created lovingly by amaing people) is not a great front-end for stuff like this. Github is very easy to get started with and excels at code hosting. As for the blockchain that's a terrible idea, there are so many things wrong with it including the cost to push all of that data into the blockchain and the fact that while source code can be small it isn't always and it's magnitudes of times larger. Right now each block is 1MB and blocks take some 10 minutes for just 1 confirmation so you are looking at < 1.7KBpss (13.6Kbps) "upload" speeds. IF you actually attempted this you would have to have some sort of header on each transaction to tie it all together which lowers the speed even further. I'd bet money that if you started uploading nodes would either ban you or the core devs would do something to stop the chain from being filled with shit that now has to get replicated to 10's of thousands of machines across the globe.
I received a lot of downvotes but my comment was a bit ironical since in many forums (even in HN in the past) when someone talked about backups many people suggest the block chain.
I said: With the current and future block size it will take sometime to make it happen.
The absurdity of that suggestion it not absolved by the fact that someone else has said it before, or by the fact that you said it will take 'some time for it to happen'. It's completely not an option for the migration we're discussing.