Thanks everyone for your replies.
As far as what the final project would look like: I was a drummer in bands from the late 60's until '83 when the MIDI thing came out I started sequencing and that went on for plenty of gigs and recording. I ended up sequencing a lot of songs (like 1000 or so) but they never seemed like tracks like some people thought. To me they were more like artificial intelligence. I ended up using the same instrumentation on near every song, so it was like a band that had been together for a long time. The bass, drums and "muted guitar" tracks seemed to turn into actual individuals over the years. I've always, well since the 80's, pictured that I'd end up with a few droid musicians on stage. It seems like to be the simplest I'd need a drum guy, a bass guy and another "everything else" stereo guy. These would be piles of gear, but ideally very pleasing to look at. Since I'm in Hawaii it would no doubt have a tiki, bamboo, grass skirt theme like most of my stuff has. So for instance the drum guy would be a kick drum, a snare and a stereo pair of speakers for the rest (toms and cymbals). The kick would have a large calf kick and if electric would have a say 100W amp (I'd use car stereo amps) for just the kick. The snare would probably be another 100W amp with a 12" speaker and "the rest" would be some sort of left/right amp/small speaker setup. I would aim to make it so you saw nothing but wood, bamboo and grass skirt stuff. The electronics would be hidden so it would look like a "what is it?". The bass guy would be just a 15" speaker and amp dressed up in similar tiki garb. Lots of carved palm tree stuff. And so on for the "everything else" guy. I've made a lot of the gear I use on stage so the carpentry and electronics is something I think I suck at but I always seem to work it out.
I've been watching a YouTube vid about this place in Nashville that records bands live with vintage gear, often with just 1 - 3 micas. So that's my idea. Get my musician friends over and record along with my MIDI droids live, no overdubs and do all the mixing by mic placement. Use 3 mics, Neumann U87 for the middle, and 2 Neumann KM84's panned hard left and right. No overdubs, a recording of a live event. No headphones, lots of track bleed, no problem. I've grown very tired of the "laying down songs track by track with headphones" thing.
Right now I'm thinking it would be best to build the drum droid (better name please) with a speaker facing into a kick with a calf front head vs using robotics. I need to try it to see how it works. I have a beautiful 28" (thunder sounding) old Rogers marching bass drum shell that would be a possible candidate. Years ago I bought a pair of Infinity speakers at Goodwill for $10 or so. They were a Made in USA not-cheap product. I re-foamed the speakers and each cabinet had a woofer (8" or 10") and also a resonant speaker of the same size. The resonat speaker had no voice coil or electronics going to it, but just pumped with the pressure the real woofer made. It was unbelievable how much bass it put out (although the sound of the speakers, the cones being non-paper, was horrible). Since then I've wonder if someone could mount something like that in a bass drum, in the from head. Well, this would be a bit like that with a speaker facing into the drum and a calf front head. For now it seems like I should go with the electronic (sound sample, I'm using a Roland SC-8850 SoundCanvas mainly) method and see if it is ok. I'm concerned about the latency of robotics and if it would vary with the tempo of songs and fluctuating ac voltage, stuff like that. The sound I'm looking for with the kick is a super low sound with hardly any high end, like you get when you use a huge lambswool beater, not played loud but having tons of bottom. The much I do is sort of radio jazz/whatever/Zeppelin/Miles/Hendrix/Jobim if that makes sense. I use a lot of Fender Rhodes and don't need to play real loud.
So for now I'm going to concentrate on making it sound and look good, not weigh a ton and be as simple (wish me luck) as possible, but long term it has to involve robotics.