I recall some piccies of mouse tanks, brewed up for Star Wars figs, from before the turn of the millenium. Had a go once or twice, never found the right config.
Yours are stunning!
As for the VTOL, I rather like it being 'no scorpion'. Without the BFG's on the side, it's utilitarian look would make it dicey, and thrilling, on the battlefield.
'We can't fly this into a fire fight! The odds are we'll be swatted like a fly in the first...'
'Never tell me the odds. Prep for insertion!'
Doug