I think this could be a very good thing. I would like to come in as an "old guy" single founder, and hook up with a Bus-Dev guy(or gal). I have quite a few ideas, but most would need a few people to get off the ground. A few things that I am interested in are: Solar, bio-fuel, an Arduino competitor, small PMSM motors for the medical industry. I was thinking that if several "single" founders were selected, there could be a few arranged marriages. I am guessing that after seeing quite a few groups the Y Combinator crew would have a good feel for what might make a good group