To my knowledge, CBS never said no to a T5 Constitution, per se. The deal states, that there would be no TOS Constitution at T5. Cryptic could profit nicely of this, if they withheld it for a longer time, since people who desire it, will have to make do with other ships as supplements, before they can get their hands on it. I'm pretty sure we'll be seeing Cruiser Retrofits in maybe a year's time.