A new rugged phone from Casio has shown up on the FCC website. The Casio Boulder is a flip phone that looks similar to the GZone. Little is revealed by the phone except for that it features CDMA, EVDO and Bluetooth radios.
The GZone is currently sold by Verizon, so it would seem reasonable that the Boulder would be headed there too, although there is no indication in the FCC documents.