I would think it is a relatively straightforward job to build some sort of Muscle Commer, tho personally not to sure where to start.
Plenty of room in wheelarches for lowering and widening the track. Front suspension is off a Humber car and is quite sophisticated. Rear end is plain old leaf springs and lever arm dampers. I was having a poke around on saturday and there is now no oil in any of the shock absorbers, so i will need to do something before the next MOT. I would also be concerned by the braking power, the minimum would be to add a servo.
V8 as per previous posts, there is plenty of room etc but I doubt the axle would handle the power for very long.
Paint scheme, I liked the earlier suggestion of Racing for Holland. I would prefer tho Racing For Holland and Barrett, a sort of organic wholemeal Commer.