This is the keyboard I (and a few others from the old Edge board) have. I think it's a good size for travel (roughly the same as the EE itself), thin but full sized keys.
http://www.amazon.com/Super-Slim-Key...dp/B003PHJJV6/
And they've been unavailable for the longest time, but now that I check the link again, they have them. I really like it.