I don't think anyone that set on getting a Verizon iPhone just started a new AT&T plan on December 25.I really dont think they'd announce before jan 25th even if it were coming, because they don't want people to be in the 30-day-return-window for all the phones bought for christmas
Will there be a lot of people who jump ship? Probably, but exceedingly few of them will do it mid-contract.
It's certainly possible that AT&T has renegotiated a time-limited exclusivity, such that AT&T gets the new iPhone in June and Verizon doesn't get the CDMA version until the following January. This could continue for a couple more years. Who knows?I'm thinking that the Verizon iPhone will be announced in January, but go on sale in June. Thus keeping in line with their traditional iPhone release cycle. It's hard to imagine Apple having two different release cycles for the same product in a year. That would really make things worse as the earlier release on CDMA would have any new features and the the later release on GSM would have to wait six months for their new features.