Hi Emily -like the sound of your new frame. Sounds like a good project for the winter too.

I personally would steer away from 650 wheels for the following reasons:

Here in the UK it's a lot hard to find tyers & inner tubes that fit 650 wheels - they tend to cost more and there's less choice. Secondly as a club mate found out, most people seem to have the larger size wheels. He got a puncture on a club run and had forgotten to pack a spare inner tube. So everyone stepped forward to offer theirs only to find he had 650 wheels and none of the tubes would fit. In the end he had to put a patch in the inner tube on the while sitting on roadside!(Sure did take a long time to find a bucket of water... )

I know these aren't actually mechanical reasons for not to use 650's -if you're not very tall and have a nice compact frame they might suite you. Why not go to your LBS and sound them out. They also be able to take into account you body shape.

These are just my experiances...