I am a big 7mm fan as well. I am in the process of building a .22 Creedmoor, but once that is done, I will probably do another build using the Tikka 7RM that I have. I like the RM cartridge, but I am getting away from belted mags for no other reason than personal preference.
I thought about building it into 7PRC, but have decided on doing a 7 Sherman Mega instead. The two factors driving my decision are 1) I already have a .338 Mega and I love it. It is a super fun cartridge to develop loads for and it flat out shoots. 2) I am a wildcat guy at heart. Great brass is available for the 7SM and it provides that "little bit extra" over the SAUM/PRC/RM.