Maybe you should start by thinking about what it is about the JCM2000 that makes you want it. Then see if you can get that through something less deafening and more convenient to move around. I have come to the conclusion that in these modern times, there is certainly no need for anything over 50 watts, and really anything over 30 watts. The stupidly overpowered amps and full stacks are a relic of the past...from when that crap was actually needed because the PA couldn't handle amplifiying the distorted sound. Nowadays, if you need more volume than a 30 watt can provide, then you're in a room where the amp by itself won't give proper sound distribution, and it should be run through the PA anyway.
You know a lot of the classic, "holy grail of sound" tones that you've heard on recordings? A lot of those are from 18-30 watt combos, not 100 watt stacks.