Have you thought of wrapping some string around a tree and pinning the cards to the string (with clothespins). I saw this on another blog and it looked really cute! People circling around the tree looking for their name. you could make it cute with some ribbons and/or other things pinned in with the cards.

You can DIY – use two boards (of whatever material you choose) and attach them together to form an “A” so the board display will stand on its own, whether it be on a table or on the floor.  Paint or decorate the boards to fit your wedding theme.  You can use both sides to display your escort cards, so the board dimensions don't have to be so big.

OR 

You can DIY and make two “smaller” boards to display your escort cards!  This may also make it easier for your guests to find their cards because everyone isn't huddled around one board.

OR

You may want to consider attaching your escort cards to your wedding favors and putting them in baskets, apple crates, or galvanized tubs or buckets on a table.

Hope this helps!