... I do have more too many pedals than I have too many seatposts, by far.
That kind of stands to reason, I think. There are two basic pedal threads (well, not counting Schwinn stuff), so in a pinch there are probably plenty of pedals you can just slap on your bike, unless you are building up your first truly Francophilic bike. OTOH, the variety of seat tube diameters is almost endless, so you have to have a whole passel of seatposts handy to have a hope of just reaching into your parts bin coming up with something which will work.