Custom Bike - 650 vs. 700 wheels

[ilima]

how easy/ difficult is it to switch between 26" and 650c wheels? do any certain types of brakes facilitate this?

I think long-reach calipers allow you to do this. And a brilliant suggestion on Triskeliongirl's part.

I saw a posting of a bike built up like this a couple weeks back. I wish I could remember where, though!