Maybe you can buy a used wiener mobile and unlock the banana skin for it.

A yellow vinyl wrap plus fabricating a couple of cones for the ends of the wiener to morph it into a banana sounds a heck of a lot cheaper than fabricating a fiberglass banana shell from scratch, I think you’re onto something here! I’ll start the GoFundMe and work on procuring a lightly used wiener mobile, GP will be cruising in a banana mobile by next summer :)