You might check out a company that I used to own, BitPusher.com. They host and/or manage infrastructure for dozens of startups, including a few YC startups (Wufoo, Meteor solutions (I think), and am pretty sure they're working with Posterous now).
It's a cool setup, we built it with the idea of replacing systems administrators in a start-up, becoming part of their change management process, providing architectural guidance, and proactive management of customer infrastructure. They do dedicated servers in their own datacenter, as well as having great pricing with SoftLayer due to a pretty strong relationship there.
My old business partner, Daniel Lieberman, still runs BitPusher. Tell him Michael sent you.