Yep, like Dave says I have the Mini Spares alloy 4-potters (NOT the Mini Sport ones, they apparently are a bit more flimsy and give soggy pedal feel as they flex).
I couldn't be happier with them, I've driven Cooper S discs (unassisted) and they're much heavier to use.. unassisted, mine need only as much pedal effort as the old drums did. Feel is good, confidence is way up there (particularly with good tyres), plus there's the novelty factor of having something a little different

The only downside to the 4-potters is that with the standard brake master cylinder the pedal travels about one quarter stroke before the brakes really start to work as they take more fluid to move the pads.
Wheels are a problem though, I've not tried many but so far only my standard-offset Contessa's will fit and that's a close thing.