No offense to the suggestion, but I'd highly suggest not going with 650 wheels! There's no reason you should work that much harder than everyone else on the road just because you're small! You'll spin your legs with more cadence (expend more energy) to get the same amount of speed as someone on 700 wheels.

The Ruby is a great choice (sorry to beat a dead horse). And, it comes in small sizes that are built really well. One of the girls that rides for Aaron's has a Ruby Pro that is a 44! I've never seen a bike so small for an adult! It's TINY...still has 700 c wheels and she LOVES it!