Mini stompers were something that Tyco continued on with after they took over the stomper lineup. They are smaller than regular stompers, are powered by a lone AAA battery, and work via a simple on/off switch. I don't have official lists of all the models and colors, but the big distinction seems to be that they sometimes came in packs of two instead of just one mini per package. If they arent in the package any more, you can flip over the mini to tell who made it. It with either say Schaper or it will say:

 

STOMPER® MINI 4x4
TYCO
PATENT PENDING
MADE IN THAILAND
 
 

grey Jeep Cherokee "Chief"  
 

red Audi Quattro #4 -- Schaper made a similar red #31 Audi  
 

notice that Chief is in both packages  
 

more double packs (60838) plus a single unit (60837)