I also have a Salsa El Mariachi (HT 29er 1x9) and an '06 Rockhopper with bad wheels (need to find cheap wheels so I can sale or have as a backup).

I wouldn't mind older used frame. As long as geometry is relaxed, it is steel, there are braze-ons for fenders AND racks and bottle cages, no heel strike, etc. However, not sure what to be looking for on CL.

Plus, ff I built from frame it would be my first time do anything major. Though, I thought it would be a good time to learn. The whole idea is that I figured I could get more selling the CC then parting out (plus less hassle for multiple transactions/shipping).