It appears that the Hartmans have at least a couple more auctions up their sleeves, and they're not waiting a few more weeks to share them.
Both of these auctions are for prototypes of what they called "Go-Bots" in Generation Two. These are "Hot Wheels"-style cars, complete with free-rolling wheels and compatible with Hot Wheels race tracks, that turn into robots. Unlike all the auctions we've seen up to this point, these toys were never produced in packaging, even in small quantities. Had these prototypes made it to that stage of production, the colors would have been different.
In each of these auctions, two of the three molds available were eventually released as part of the "Robots in Disguise" line, but the third mold has never seen wide production, possibly because of a mold problem that makes the robot unable to hold the weapon that accompanies it.
Both auctions represent one-of-a-kind opportunities to own a piece of Transformers history. Expect the bids to go quite high. They're each at $34.33 right now.