Can anyone else back this up? If it's true, than every carrier could be used, no?
I think there is a difference between the LTE standard supporting "passing" a call to a CDMA standard tower and a single LTE chipset supporting handling both sides of that "pass". I strongly suspect that the first-gen LTE chipsets will support LTE alone and allow a second chip to take over for legacy nets, and then an evolved design will emerge combining LTE and CDMA in one, and LTE and GSM in another. Third gen is when you might see all three in one chip, but I don't see that as likely. There's more than just the chip that needs to be different to support CDMA and GSM: the antenna system, for instance, is rather different.
IMHO, if it were "that easy" to get GSM and CDMA in a single phone it would have been done already.
So, back to the point the majority of folks have been saying: when Verizon supports LTE Apple STILL will not support Verizon's CDMA network. And, of course, Verizon's main advantage right now is it's CDMA network, which is astounding in a good portion of the US. The same will not necessarily be true of its LTE network unless Verizon makes a major legacy-customer-pissing-off move to prioritize LTE signals in the CDMA/LTE shared bands (having the low-frequency CDMA bands in many major urban areas it the key "secret" ingredient to Verizon's success ... along with of course investing in the switching hardware etc to handle it).
In the end, Apple might start thinking about supporting Verizon when Verizon has made a 75% or greater transition to LTE,
unless they decide that supporting CDMA for the handful of (large) markets is a good route forward.
Personally, I think Apple's more likely to end up deciding that having two versions of the iPhone (CDMA-compatible and GSM-compatible) makes more sense than just ceding a large chunk of the US market. That's what Verizon should be hoping for: that Apple sees the number of people that can not and will not buy an iPhone because it comes on crappy networks in the US. LTE is not likely to save them.
(Note that there's a good chance, on the other hand, that the
marketing around the Verizon launch gives a lot of credit to LTE, if and when it happens ... but you'll know that wasn't the real reason the moment someone looks at the FTC numbers and sees that the Verizon phone and the AT&T phone have very different filings because they have very different radio hardware.)