Here's an idea if any 3rd party people want to give it a shot: A simple removable "shell" to make DotM deluxe Roadbuster into his movie vehicle mode. I think it would definitely be possible. The shell would have two halves with Mech Tech pegs to go in the holes on Roadbuster's doors. (The pegs inside his arms may need to be cut off so the doors could stay in place while the shell pegs go in the holes.) Then the front and backs would also tab together. I think the toy could still use its original wheels, windshield, and roof... This might also be possible in some manner for Human Alliance Leadfoot, but probably more difficult to pull off...
If the DOTM line hadn't been ended prematurely thus ending my interest in Movie stuff, I'd definitely be in support of this.
TreadshotA1 made some Shapeway set for TF Prime Vehicons that use a very similar idea... Zirca Ailon Army-Builder Kit by TreadshotA1 on Shapeways Zirca - Legion Vehicon Drill Conversion Kit by TreadshotA1 on Shapeways I'll have to see if he has a thread for these here...