>>mwatts+(OP)
Actually I think Bill would be a pretty good candidate. Smart, mature, good at first principles reasoning, deeply understands both the tech world and the nonprofit world, is a tech person who's not socially networked with the existing SF VCs, and (if the vague unsubstantiated rumors about Sam are correct) is one of the few people left with enough social cachet to knock Sam down a peg or two.