I love the Sound Devices ADCs they've used (in the 7 series and usbpre2), but unless you need a usbpre2 for something else (head amp, dac, preamp/adc, etc) then it doesn't make much sense. Apogee had a small unit after they axed the minime that might be interesting to look at.
Really, a Sony M-10 will do the job, and unless you've modded your analog stage of the ua-5, the m10 will likely do a better job. I could tell a difference when a comp was done with the m10 against the 722, but it wasn't a slouch.