Why not a 7SAW? Same bolt face as your 6.5CM so wouldn't have to change that. I enjoy shooting my 6.5PRC and wonder if I would have been fine with it in a short action instead of the long action route that I went.
Keep in mind I have heard the short action may struggle to feed the 156 grains in the 6.5prc. I have a short action 6.5 prc but have never tried shooting anything heavier than 140gr so I can’t say if that is true or just internet rumors.