FWIW you can get a Asus Aspire Revo for $199 which seems to be able to do this. I bought one but haven't hooked it up yet.
I love it as a XBMC front-end to my UPNP linux server; it is super quiet and uses very little energy when it's sleeping, and works fine on HD content. As far as Hulu goes though, it just doesn't cut it (YMMV, I didn't try very hard).