I’m quite happy with my Yamaha THR 10 V2 http://goo.gl/tMAlM0, not just for home practice but also on stage. Great sound! There are 2 major shortcomings:

For those of you who also want to tamper inside, the photos show how to open the case. 5 self-tapping screws with recessed cross (2 at bottom, 3 at backside) and 4 Allen screws “Ikea size” :).

Hours later, correcting myself. There are foot pedal hacks:

maybe…