While I can't think of a specific example, there are related precedents: consider the advent of the Mann Co. Store in TF2 where players purchase game items with real cash. There is definitely a model to be made off players with disposable income who want to be the top dog.

Your second question is a reservation that I have as well. We have already witnessed a huge influx of people coding up DCPU-16 software for free, but such programs are only related to the software engineering side of the spec rather than the actual gameplay. Obviously we know less about the latter since few details have been released, but in the competitive game I imagine it could be different. For example, to build a really awesome weapons system and then share it with other people seems a bit counter-intuitive. So there may be room yet for a business built on custom, clandestine code for a player's ship.

Gamers are already a demographic with money to spend. This could be seen as a worthwhile investment to some. If you are interested, email me and we can talk there.