You want to mount a band brake over the clutch drum, correct? There really isn't much fabrication in such a simple bracket, and no such thing is produced AFAIK, so you will have to build one.
that thing is sick! if you put a band brake on clutch and chain snaps, there goes your brakes. what redsox is saying is that you shoud buy a brake drum and put it in the axle that turns the tread, if your using this in the snow i would suggest a better brake then a band