Oh dear! I just found this thread via Google, as I was looking for View From 'pants'. I've finally decided that mine (bought in 1992 while training for my first and only, so far, 1/2M) have got past it. Ironically, that's only because I did some painting in them and they've got splattered. Guess I shall just have to carry on for another few years.
Just in case anyone else stumbles on this thread, I thought I'd post a follow-up...
After a bit of browsing several sites I discovered that ASICS, Nike, and Scott all do kit in the larger size ranges.
One of the problems that pear shaped people have is keeping their trousers up - the same applies to running kit. So, I'm going to experiment with a pair of Scott's padless but bibbed cycle tights - they're very reasonably priced and available in two larger sizes than even I need them.