So here are some pics of where I'm at so far. Didn't get anything done on it today - the grouting took longer than I thought, and my daughter and the grandkids are on the way over now.
Top view
Side view
Iso view
So I'm currently looking at making some smaller CD mounts that will mount to the lower tray (which I didn't model up yet). They are flush with the top of the chassis - I might be able to tie them into it also instead of a plate tieing them together.
I'm thinking of trying a mount set up similar to a flux mount - two straps around the motor, and they would mount to the upper chassis and be slotted side to side. But, this wouldn't put the motor in direct alignment with the spur...not sure if thats going to be a problem or not.
I think I'll extend the upper chassis plate to one side to give me a battery mount location. Or, if I can get dimensions for the XXL, that might give room to mount it on center...