A GSM version would not be $150. Although VirginMobile and BoostMobile are prepaid no-contract providers, the CDMA versions are locked into those services and so I wouldn't be surprised if there was a minor subsidizing of the phone knowing that they'll make money over the long haul. Heck, at $150 it would make a great alternative to an iPod Touch.... throw in a 128GB microSD card... and never activate it with the service.
The Aquos Crystal is a phone that I'm really itching to get. I'm currently on StraightTalk with an iPhone 4 and I'd love to get a GSM version for use with ST.
But our family has had great experience with VirginMobile over the years and so I'm fine with going back to VM.
From what I understand, the Aquos Crystal is going to be an exclusive to Sprint/BoostMobile/VirginMobile. I suspect that if there is a positive consumer response to that handset, Sharp will commit to bring more to the US. I'm not willing to wait for that possibility.