What about putting up a horizontal length of Unistrut/Kindorf? It will work like the 2x8 and is a little less obtrusive on the wall. The multiple attatchment points will help spread the load too.
I disagree with both points above and think Unistrut (or similar) is a great solution.
1. Unistrut's primary use is to support conduit--in any orientation, and is very often mounted horizontally on walls to support vertical EMT runs and enclosures.
Most of what I have used is either factory Forest Green or bare steel, but takes "Technician's Magic Cure-All" (flat black spray paint) as well as any other metallic surface.