Um, you want a mixer that doubles as a control surface ? Not sure if that exists. Usual setup is a control surface as well as a separate audio interface.
Mixers with USB (or FW) connections to computer simply echo the input channels as an audio interface - not the faders side of things.
However somebody may have a suggestion for a product that does both.
Control surfaces I have used (with success) are Behringer BCF200 and Mackie Control.
About the only things out there that come close are:
Mackie Control (midi). It will act as a control surface inside of Vegas but no external mixing.
Tascam 1884 (discontinued/used/firewire/midi) It will act as a control surface for Vegas in Mackie emulation and has multiple ins/outs, analog, spdif, adat. All can be recorded into Vegas. However many functions on the Tascam don't crossover into Mackie to Vegas. You will have basic jog shuttle, play, record, ff,rw., touch sensitive motorized faders that can record automation.
Presonus mixers appear to be slightly supported.
Check the Pro 11 users manual (external control) for more detailed info.