Go Jelly Bean man, contact FeraVolt, Achotjan and Tof37, these are the guys making great progress with this. Another great developer like you will be a great help to them and yourself. You can still continue working on your GB roms, this is what FeraVolt also does, on the side he also is working on JB.
Phone: Sony Ericsson Xperia X10i (Sensuous Black)
ROM: Somc Debrand Engine Project | RC3
Android version: 4.1.2