This is certainly not the best designed of Mini derivatives, neither the prettiest. The idea must have been simply to take an axle grinder and get rid of as many original body parts as possible, loosing as much weight as possible but not too much of the basic structure. Wings were replaced by something preventing the mud from flying into your face, and there must have been something of a 'rear deck'. Is it named 'Fargo Tiger'? The paint scheme certainly fits that name. But for the rest this is an unknown car at an unknown autocross event, probably somewhere in the 1960s...
UPDATE 8 April 2013: Richard Hawcroft wrote: It looks to have started life as a van, judging by the wheel base – look at the length of the sill. I think he's right!
'Fargo Tiger' autocross special is, erm, somewhat rough around the edges
Picture courtesy Richard Heseltine