I wound up doing a magnetic board, and thought I'd show a picture of it. I bought a 4x6 ft. piece of 20 gauge steel (about $65, 30 lb.) from a local sheet metal place, and a couple of 6 ft. lengths of moulding with a rabbett (slot) pre-cut in the back from a lumber yard (<$10). I took my x-rite color checker in to a paint store and had them match the neutral gray that I wanted, in a flat latex. That + a spray can of metal primer was about $20. 2 coats of spray primer, 3 coats of latex and it looked pretty good. I screwed the bottom moulding to the wall dropped the metal in to the slot, and screwed in the top moulding. It works great, with cheap magnets from Office Max. Letter size prints only need one magnet, 13x19 need two. It would probably look better if I put moulding on the sides. Also, the paint scratches very easily. I probably should have used enamel. The color (or lack thereof) is perfect, though.
All in all, it's a great, cheap way to look at prints.
BTW, sorry for the crummy pix - on-camera flash mixed with poor existing lighting. Trust me, the color looks good in person.