That, I have not heard. Mine is working flawlessly, and the quality of the build is the best of all the Blackberrys I've ever owned. It has the best feel in my hand of any I've used as well.
Pulling it off the line during the H@H rollout is certainly the prerogative of T-Mobile, and they could site numerous reasons why it would make sense. Like avoiding the confusion with consumers over which model works with WiFi. Yeah, it would be a lame reason and I wouldn't swallow it, but I've heard dumb corporate moves explained even more lamely before. I don't know if I'd go so far as to call it unethical, but it's definitely a little on the fuggazey side.
Having quality control problems would certainly fit with it disappearing and reappearing later. Iron out the kinks in production. It would also fit that they'd want to keep something like that under their hat. I just think we'd have heard more griping about it in the 8800 forum. Still, it's a strong possibility.