I had a white ( coloured ) Metal board made up by a fellow I know. I'm in the Fabrication business, so the steel was no problem. I wanted to get it powder coated, as paint can rub off on a poster even when dry. So contacted a fellow I know who has his own business. He bought the steel cut it to size and had it powder coated for me. It's in the garage at the moment as I've changed my mind on how and where to hang it, but when it's up I'll take a pic. I had it made about 5'X4.5"Maybe a bit larger, can't remember at the moment, as I don't want it too big, but big enough to fit certain larger sizes, so it will take a "Quad Royal" no bother.
Anyway, this cost me nothing as I put work his way. However I asked how much it would have cost and he said around £50-60 all in. So it is a cheap option. I am going to get the fellow something as He is looking for a Bond poster for his Film room, so when a nice one turns up I'll get him it. We maybe tight up here but we do like to show appreciation...