Hummer roof track bracket?

[MAC]

Is there such thing as a roof track bracket? as the 2 brackets that holds the roof bar. I found some neat wireless remote control cameras which I can rotate 180 degrees up, down left & right. No wiring required except at LCD and receiving unit. Only about $170 for 2 color/night vision cameras with radar like curve plate antennas and remote control plus hardwares, LCD not included. There are few logical points of installation, in addition to inside the Hummer through dark tinted glass. Mounting on rear lense guard is too low thus risky to theft, the roof looks like the best spot. If roof track bracket is available, then I can mount one on each side at the rear of Hummer. No drilling is required.

If you know such brackets are available, please kindly inform me.