A couple of the Multiforce guys are going to be on my Two of Cups, and while playing with my Tackle (no jokes please - GWAR, DF, I'm looking at you...) I realised that if you repainted him and swapped his head with Mach's (who's the other fig on the card), he could actually make a pretty cool Prime.
I don't have the spare figs, but I pulled some pics from TFU.info, and mucked with my PaintShop, and here's the result...
Robot mode:

This got me thinking about doing the rest of the team as classic characters too, so I started with Waver and repainted him into Seaspray...
Robot mode:

EDIT:
Wing as Jetfire
Robot mode:

Vehicle mode:

Any other ideas..?