Not the GP, but I was able to pick up a new 4gb model from the Acer online store a few weeks ago (the Canadian store - I don't think Acer is selling it new in the US anymore).
If you're unable to find one I believe the new Dell Chromebook 11 is fairly similar.
Marginally relevant - are ARM Chromebooks any good for development? I've been considering getting a Samsung Chromebook 2 when it comes out, but I'm concerned that important software won't be available for ARM.
Anyone running crouton on an ARM Chromebook care to comment?
If you're unable to find one I believe the new Dell Chromebook 11 is fairly similar.