Update: I did finally find someone in the UK who could help. Spa Cycles turned me on to their colleague John at Jade Cycles who has an
eBay store, and therefore has access to eBay's international shipping rates. He put together a package deal for me:
2 Ryde Sputnik 36h 700c rims: $49
80 Sapim Race butted spokes & brass nipples: $64
Shipping: $27
Altogether, $140. I'm happy with that. Thanks to @
revcp for the tip about Spa Cycles, that led me in the right direction. Anyone else looking for Ryde rims, I wouldn't hesitate to contact John, he was very knowledgeable and easy to work with.