At a previous job, we had a large piece of sheet steel, about 48" x 72" which was glued to a plywood back.
The steel was painted white with a roller to give a little texture and framed with a moulding.
We had this hanging (with zbar) in the design area.
We could then take the client's artwork and put it up on the board with felt padded magnets.
The white metal board gave a neutral background and with the artwork held up by the magnets we could then hold up corner samples so the client could step back and view the design.
This was before "virtual" design and computer programs to facilitate design, but it worked.
I guess in your case it depends on if the board needs to be magnetic, or if it can just be metal with stick-on magnets.