Believe it or not the lowly Wrangler S came equipped with what you are looking for. In the absence of the Jeep factory radio, the Wrangler S came with an instrument panel storage box as seen in this pic(11). You might try some salvage yards to find a used one, or take your chance at the dealership. The part number for the storage box is 5500-7711.
Jeepsareus 1-877-533-7787 lists the box at $16.58 but you'll have to call them to make sure they actually have it.
Hope this helps.