2007 + 5 year exclusive contract with at&t = 2012.
cdma = no voice & data at the same time a key feature of the iphone.
lte = at&t and verizon's (not to mention t-mobile, vodaphone, and china telecom) next generation cellular technology. verizon begins roll out this year with completion set for 2013. at&t will start roll-out in 2011
do the math.
apple will sacrifice a lot in the name of simplicity, be it interface design or the retail shopping experience. they notoriously "knifed the baby" when they deleted firewire from the ipod despite being the creator of the standard and firewire being superior to usb, all in the name of retail simplicity (e.g. the only choice the shopper had to make was color and capacity, no technical knowledge). a cdma phone complicates every stage of the phone - design and development, prototyping, testing, production, marketing, retail, shrinkage, returns, support, warranty, repairs, logistics, partners, contracts and probably a dozen other things i'm not thinking of.
best guess there is a cdma version of each iphone, much like os x on intel, taken to a certain level of development and kept in reserve just in case there is a major problem with gsm carriers and/or iphone sales start to decline precipitously. it would be shocking to find apple doesn't have a minimum quarterly sales target for at&t that allows apple out of their contractual obligation. all the reports are based on these prototypes and possible apple enquiring to manufacturer's capacity as a fall back scenario.
but it's not like apple is struggling to sell iphones right now. january 2012 an lte iphone announced available on at&t, verizon, t-mobile. jobs' trademark "one more thing" biplane - a new version of airport with an lte radio embedded allowing you to ditch or augment your home cable/dsl/dialup" ok that probably isn't going to happen, but the 2012 lte phone will.