Lookin' good, Rod.
Why not put the gearboxes on the center wheels and use two output sprockets (one to the front and one to the back)? This will eliminate the possibility of this drivetrain becoming a 4wd (3wd on one side, and 1wd on the other) with the loss of just one chain, or a 2wd with the loss of two.
Sorry if this was brought up earlier in the thread… it’s almost 3am, and I’ve been doing something that a lot of 21+ year olds tend to do
-Bill