In a similar vein, I'd love to see YC take on one or both of the following:
1) Do at least one application cycle completely blind. How could you accomplish this? Much like in the concert auditions where this was first tried, put people behind a curtain--and then use technology to change their voices so every voice sounds the same. I think it would be a really cool experiment to see if different types of companies or a more diverse founder set would get funded.
2) Publish more stats on the success of YC companies, and publish stats on % of female(, black, ...) founder applications submitted, % accepted, % funded after acceptance, etc. Of course, I'd fully expect that this would be "opt-in" from the founders as well--i.e. each set of founders would need to agree as part of the application to have their data anonymously shared. You could also share data on % who opted to not have their data shared. (Techstars is doing some great stuff with their stats here: http://www.techstars.com/companies/stats/ )
I've talked to many female founders and YC does have a reputation as a "frat house" (I told one of the YC partners that personally when he asked me to apply.) I decided to not apply to YC and instead was in the first Techstars Austin cohort, which was a fantastic program overall. Techstars definitely seemed more welcoming to women from my perspective as a geek-turned-tech-entrepreneur.
I'm hoping this is the start of breaking down the "frat house" reputation around YC and getting more women actively involved with it.