In reply to GaryK:
My mate has a 35.5 inside leg and I sold him some Arcteryx bibs which had a 34 inside leg. He simply got a decent pair of lightweight goretex gaiters, had them modified and had them sewn into the bottom of the trousers to extend them so they fitted perfectly over his winter and ski boots.
Cost him about £30 to get it professionally done and he reckons it is the best thing he has done. Like you, he spent an age looking for a pair, buying some from shops online hoping they would fit but they didn't, always something wrong, the fit etc etc so this was the perfect solution for him.
Might be an idea? Den