The pruning method of choice seems to be evaluating developers based on their contributions to open source projects. You have to be at fairly proficient to successfully submit code to a well run open source project, because bad patches usually won't be accepted (fairly... well... bad... usually... not a very strong sentence is it :p).

AFAIK, the YC route is similar but a bit broader: ask them for any kind of interesting projects they have built. You would need to have someone technical take a look at them (or you could probably post something here and you'd get half a dozen people's opinions on the quality of the work).

Depending on how difficult the idea is to implement (and I realize that this is hard for you to gauge), you may be able to go the Guy Kawasaki route of outsourcing the development. The general rule of thumb the community seems to have agreed upon is that as long as your chief product isn't technology (i.e. technology is not your core focus), then outsourcing at least the initial build is not untenable.

Feel free to shoot me an email if you want to discuss anything in private, I give you my solemn vow not to leak your project... anyway, I have too many other things to work on already :)