I have a halogen canister light with NIMH battery, wet connector, "test tube" lamp and video reflector. I wear the battery canister on my hip looped through my BC waist strap. Before my current bc, I wore the canister on a weight belt.
The video reflector covers approximately 100 degrees. Sartek sells these items, but lists them separately because they mainly sell HID and LED systems. I would recommend going with a single lamp and 4.5 AH battery canister with wet connector. If you want dual lamps, you can get 2 separate 4.5 AH battery canisters or a single larger 9 AH battery and a "Y" cable. I think 2 separate canisters offers better flexibility and a lower initial cost since you can get the 2nd canister in the future.
The 4.5 AH canister is 2.3" x 10.5" and fit very snuggly on your hip under your arm. The 9 AH canister is 3.75" x 7.5". They are 1 lb and 2 lb negative respectively.
Burn times for a 50 watt halogen bulb on a 4.5 AH NIMH battery is approximately 1 hour. While that may sound short, the beauty of halogen lights is you can turn them on/off instantly. For video use, that easily lasts me a full 75+ minute night dive or 3-4 day dives with lights for macro shots. Night dives I use a standard flashlight for spotting and only turn on the lights when recording.
I buy my halogen bulbs from bulbconnection. The 50 watt Osram HLX 6410 bulbs cost $2.50.
So, in a nutshell, halogen lamp, video reflector, 4 AH NIMH battery canister with wet connector, NIMH battery charger and a couple of Osram 50 watt bulbs, for under $600.