Battle Grid Idea

I was brainstorming last night and came up with an awesome idea for a grid for fights or whatnot. I knew I wanted it to be reusable, something that would not be easily ruined or smudged and big enough for a group to see what is going on.
I came up with this idea:

• Buy a large piece of sturdy felt, about 3'x4' and light colored.
• Sew grid lines (at least 1" apart) horizontally and vertically on the whole piece.
• Iron on a few layers of interfacing to give the felt more durability.

I know I want to hang it on the wall, so everyone in a group can see it, although I am sure I can think of something like eyelet holes or whatever... hm....
It just may be sturdy/firm enough to actually put on a table top without the worry of draping or wrinkling up, especially if I iron on thick interfacing or several thinner layers :o
I'm sure I will experiment on smaller swatches first xD

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Ideas for the player's characters, monsters, and NPCs include the following backed with a little velcro to make them stick to the felt grid:

• Letters or Numbers cut out from felt, cardstock, foam, etc.
• Have each character create a coat of arms to identify their characters. 
• Inexpensive trinkets, maybe light plastic or similar.

Trying to keep it inexpensive, functional, and personalized by the players is my main focus for the grid pieces :)