From the Machine Robo line to GoBots, a wide range of prototypes exist. Most of these are undocumented and rumor only to exist. What can only be provided are mostly photos we have from catalogs. There are a few recorded Tonka and even less Bandai prototypes are out there in some lucky collectors collections. The final projects that Tonka were working on were more recolors of produced GoBots.
Machine Robo Prototypes