I'm gonna have everything on one 10" x 5" polypropylene sheet, oriented vertically landscape. Should I add a layer of sheet metal between the electronics and the polypropylene, to reduce the static electricity transfer? I'll be using 4-40 bolts and nuts for standoffs, unless there is a better way (ie, ready-made standoffs with 3/8" of thread showing, to put a nut on the backside of material). The batteries are going to be separate but next to eachother, fastened to the chassis.
The 12V+ lead will go to a chassis-mounted kill switch, and from the kill switch to a 4 row barrier strip (row 1).
The 12V- will go straight to the barrier strip, row 2
The 7.2V- will go straight to the barrier strip, row 3
The 7.2V+ will go straight to the barrier strip, row 4.
I will have a shorting bar between rows 2 and 3, to make a common ground
The arduino connection will be the barrel plug coming straight from the 7.2 barrier strip
The voltage Regulator will have a 2 pin molex connector connecting it to the 7.2 barrier strip
The drive motor controllers will have a 4 pin molex connector connecting them to the 12v barrier strip (outside wires +, inside wires -)
The stepper motor controller will have a 2 pin molex, opposite gendering from the regulator plug, connecting it to the 12v strip.
On the output side:
The wires running to the cargo box (6 stepper wires, 6 servo wires, 2 lighting wires) will be spread across two DB-9 connectors (because i'm not trusting of myself with a DB-15 plug...)
The wires for the drive motors (4 wires) will be on another DB-9 connector, with 2 pins per physical wire (for amperage reasons)
The wires for the winching motors (4 wires) will be on a fourth DB9 connector (the actual winch motor will have 2 pins per wire for amperage reasons)
The DB9's will be mounted to the electronics tray, then DB9 patches will go to the connectors mounted to the frame. Extra connection, yes, but they will be reliable connections that will be easily undo-able if necessary, and allow for quick removal of the electronics tray if were necessary.