try this seller on ebay while browsing on sportsvisionbend.com, just a quick note, she delayed my shipping last time but that's becos of a family trouble, but i assure you she's a trustworthy seller.
http://cgi6.ebay.com/ws/eBayISAPI.dll?MfcISAPICommand=ViewListedItems&since=30&userid=akp85&include=0&rows=50&sort=3&completed=1
as for which Rx pair? i recommend these, the advert has women as models for the thread 2.0, they're super lightweight and cool, the pic just doesn't do justice to illustrate how light they are:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=31415&item=5596040073
retails at $200 but if you're lucky you can get it on just one bid(starts $100), i know i did last May and won a pair of rx Thread 4.0 at $75.