Heres a idear :incoporate 2 12ax7 like the digitech 2101 i wish the kemper had a bigger lcd color scrn and master on off for effects.
I had the 2120 (purple version). I loved the idea at the time that it had real tubes, and I even bought NOS JAN Phillips tubes for mine at a pretty penny.
I have to tell you, the KPA puts it to shame. I sold mine within 6 months of getting my KPA .... and I was using it just for efx, since I had a VHT UL setup which had very nice distortion (and the KPA sounds better than the VHT as well).
I am with you on the larger LCD Color screen and master on/off (although you can accomplish this through the FC I believe).