have you seen this resent topic, http://moke.com.au/Forum/index.php?topic=2115.0
I guess it all depends on
a/ how much money you have
b/ what skills you have
a/ you could buy a cooper S set up for $800 to $1500 + and have someone fit them or import
some nice vented disc's and 4 spot calipers from the UK but you will need disc brake uprights
to go with them
b/ you could do a honda or camira conversion, honda seems the best, probably not legal without engineers report which could cost $500 + (not real sure of cost) but if done right (like bnicho)
they look almost factory (better than) and no-one would know in the advent of an accident.
buy the actual honda bits is quite cheap, maybe upto $200, depends on how good your local wrecker is.
I wonder if Hyundai discs / calipers can be made to fit, or any other late model small FWd car
as they all have the same PCD as the honda and a lot of the have a floating disc which just slips over the wheel studs and is held on by the caliper, you can get new DBA disc's from supercheap, etc for about $30 each.