I’ve been wanting to cobble one of these together for a long time
I finally assembled the pieces and did it. It uses a Pelican 1600 case.
It has two 1.3GHz video receivers feeding either two displays (heavy lifter), or a diversity controller to pick the best signal (long distance quad) plus a 5.8GHz video receiver for my little FPV pod racer. I have a DVR to record what the ground station sees. There are two antenna hookups, and a current-limited DC power supply (Kickstarter project). Zeiss Cinemizers can run off of any video channel, too.
It all runs off a 4400mAh 3S (12V) LiPo. Not sure how long the battery will last. I’ll know more after I use it a bit. But I have a few of those batteries. I could run them in parallel, I guess.