His wheel mode is pretty much perfect, but his robot leaves a lot to be desired. Scrounge's tummy wouldn't be that round, he's supposed to be a scrawny little get, not a tubby american footballer.
Another idea that was suggested by one of the lovely folk over at http://www.thetf.net/ was to use the Star Wars Transformers General Grevious Wheel Bike. Now, this guy's wheel mode is almost right, I'd need to find a way to hide those legs, and those spikes would need to come off, but this one is definitely do-able. His robot mode to quite messy looking, but again I can see it working. I think I'd probably give Scrounge a bit more of a neck, which I think Grevious is lacking. The main problem with this one, is that I can't find the bloody thing anywhere (actually, that's a lie, there's one on eBay for £40, which is silly money). If anyone sees one for cheapish, please let me know. Cheers.
My other option is to start from scratch, get the most basic TF I can find and do my best with a hammer and sellotape. This is not a good idea.
Anyway, that's just my brain thinking out loud, any help or advice you've got to offer on this subject would be great. Cheers