In reply to JoshRawson:
Have the same problem/birth defect (although sadly not matching you and luckily for me to a lesser extent). I have had a couple of good experiences with getting odd shoes, but nothing consistent to be too excited about. I think Evolv have an odd-shoe policy (but direct from manufacturer in america I think).
I did once find my foot opposite on UKC, but I think his larger foot was due to injury and might now have gone down in size. I tend to buy pairs of shoes in sales mostly. Now the only time I try to get a deal is for mountain boots as they're so ridiculously expensive to buy 2 pairs of. I have had a manufacturer allow me to buy an odd pair (they said at 20% markup but actually just charged me RRP), but I had to go to the factory and pick them off the line, and wasn't sure if they'd do it again.
Sorry not to be of more help. I've often thought about starting a shoe buying syndicate (probably not the right word) where I'd pick say 3 shoes to start off with with different fitting and buy stock in all sizes and then sell on the correct pair for 25% markup, hoping that the deal I'd get on a bulk buy+markup would balance the inevitable loss of ending up with odd shoes (most likely at the extremes of the size range). But I don't think I'm organised enough. It'd also be a way of getting a database of people so that if it went under you could put people in contact with their shoe buddy.
If anyone's interested my spare shoes are ~8 right foot and ~6.5 left foot.