I'm looking for a new/used bike for my girlfriend, but why are 46-48cm bikes (yeah, shes kinda short) so hard to come across? I was told the new Schwinn Madison doesn't measure in numerical sizes, but the small is probably comprable to a 52. Does anybody know if there is an extra small? Also, I was looking on ebay, and found a couple of auctions on geared bikes(I'm gonna get her a single speed because she never used to shift anyways) that I could convert for pretty cheap. Is there any budget frames I am missing that I can get in such a small size? This is really getting to be frustrating.