This sounds like an excellent idea from the get-go. The look of the Hop1800 should've pretty much sealed the deal - this is going to be a blockbuster handset - if only they had added a screen, assuming there's text messaging as well. But no screen and obviously no text messaging and no sell.
It comes in two GSM versions: 850/1900MHz for the U.S. and the 900/1800MHz for Europe. It only weighs 77 grams and works with over 40 U.S. carriers.