Just as arrangers have improved dramatically, so have sound systems. It is no longer necessary to have huge, multiple amps and speakers to sound great.
You can take a Bose system, or two, and sound just as incredible. You can use a small, lightweight digital mixer to run the separate outs if you wish.
All this can easily be transported without using a Uhaul!
A few years ago, there was a guy here who did much as you described. For every sound he had a dedicated source--keyboards, a rack of modules, etc. For every source he had a dedicated amp and speaker. The setup took half the room and there were very few venues hiring a one-man band that had room to accommodate his setup. Must say he did sound incredible, but I was getting most of the jobs because his setup took so much room. Also, unless you were in a really big venue, it was hard to hear that the sounds weren't coming from one speaker.
DonM