Steinberg UR28M http://www.soundonsound.com/so…icles/steinberg-ur28m.htm
UR824 http://www.soundonsound.com/so…icles/steinberg-ur824.htm
I can vouch for the preamps, I have an MR816X myself.
If you want to go cheap, and are only going to use the Kemper with it, I can also recommend the ESI U24XL that I use for home use. It seems to have a pretty good sound quality. Doesn't have midi though. Neither does the UR on a second thought. But to get midi you can just buy a $10 midi to usb converter off amazon?