Tank as a B’t
 
The patterns on the shell are particle cannons (whose shots can be fired in either a straight line or can ‘bend’ once to seek a single target). there is no cannon on top of the shell because that’s an entry point inside where the rider (and allies) can access the medical facilities or other quarters.
 
the female figure is a representation on how small rainbow dash is in comparison to Tank.
 
I was thinking of adding his helicopter gear as an add-on flight unit but that set-up is very impractical, so a gamera style flight system would be used (that or an anti-gravity system)