A Christian rock channel was brought up in other posts and I would definitely agree with that. XM had The Torch at one time, but sacrificed it to create the Southern Gospel channel, and I think The Revolution on Sirius was dropped before the merger, along with all their other Christian channels.
It looks like with as many overlapping channels that were dropped after the merger that one of them could have been used to bring back Christian rock. As it stands there are 2 Catholic channels (EWTN and Catholic Talk), 3 Protestant channels (Southern Gospel, Black Gospel, and talk) all operated by Salem, and Joel Osteen's channel. (Does that still exist or was that just temporary?)
I can't help but wonder if Salem is being limited to the 3 channels they have or if they're intentionally keeping a Christian rock channel off of SiriusXM. It looks like SiriusXM could at least carry WAY-FM or Air 1, which would give them a larger presence nationwide, unless they have an exclusive deal with Salem.