I bought a set similar to Buldozer's for my daughter's Wrangler...plastic shell molded to fit the diameter of the roll bar. Fits in same area as his picture. Was around $75, including inexpensive speakers....I think they can be bought without the speakers.
I either bought them from Quadratec, 4 Wheel Drive Hardware (both Jeep sites), or ebay under Wrangler parts.
Had to drill 2 holes into rollbar on each side and that was it.
Pops