This is my friends mini, I checked it out the other day. The neck has been re-welded and gusseted. The forks point almost straight down, I'm sure the wheelbase is shorter than stock. I really don't think it's homemade.
The only other notable feature are the axles. There is a large square nut on one end of each axle (welded? I can't remember). This "nut" mates to a tab on the frame (or fork) to prevent the axle from spinning when tightening the nut on the other end.
Please give it another look, help us identify it.
Thanks!
Tim