I've fitted a variety of LED "bulbs" with no problems, even ones with large cooling fan bodies on the back.
I have used these with a selection of 7" reflectors that I fit in the standard Bosch headlamp and rim with an adapter, they all seem to offer much more clearance for the rear LED protuberance than the rather deep standard reflector.
If you want to try a 7" lamp I can sort you out an adapter.
http://www.ukmonster.co.uk/monster/s...adlamp+adapter
Most of the 7" headlamp units available are superior in beam pattern to the standard Bosch one.