Take a look at Howse tillers. They claim to be reversable,
ROTARY TILLER- 48 [RTC48] - $0.00 : Howse Implement Company, Your source for tractor and farm equipment parts and supplies
ROTARY TILLER- 48 [RTC48] - $0.00 : Howse Implement Company, Your source for tractor and farm equipment parts and supplies