I saw a picture of a bracket similar to this on Facebook, and couldn't find the bracket itself anywhere, so I designed my own. The brackets screw to the center tower and clamp the ESC side of the connectors. Besides being much easier to plug/unplug the batteries, it should also greatly reduce the times hard landings unplug the batteries.
 
I'm working on making parts printed from this stl available on my website, Freyja's Tiny Trucks.