If they can't sell more due to manufacturing capacity constraints, why would they do it? It would add to consumer confusion and a bunch of uninformed customers would buy the wrong kind, or buy one and then complain that they can't switch from Verizon to AT&T or the other way around. It'd be rather messy, I think. Well, messy by Apple's standards anyway.
One thing I assumed there is that Apple can't adjust manufacturing capacity in the short run. If there are other factories that can be added in the near future, the CDMA phone might make a bit more sense. Anyone has info on that part of the equation?