Good question. I was going to get an extreme 744, but I blinked over the weekend, and they were gone.
It does seem weird to me that they put the Extremes on sale, then included them in the 15% off. Also weird that they would let inventory get so low. I don't know if a new lineup is coming out (seems like there would have been some buzz if that was the case), or maybe like you've suggested, they're not going to carry them anymore. Either possibility seems remote though.