So, I'm adding a lot of capacitance and about 1200 grams of additional weight. Let's get started. The body is the same width, but deeper, so I had to break the frame into two pieces (files included on this site).

These two pieces are bolted together.

The caster wheel is added.

Now, let's go to Mato as she exists.

Remove the ultracapacitors from the old frame.

Disconnect from the buck/boost converter and remove the digital meter.

Remove connections from the breadboard.

Remove the breadboard and the processor.

Remove the buck/boost converter.

Remove the face from the frame.

Install the motors and wheels on the new frame.

Add the face to the new frame--a hole will have to be drilled in the frame.

Fasten the breadboard and processor to the capacitor holder.

Drill holes in the frame to accept the capacitor module.

Secure the module to the frame, connect the wires and Mato is ready to run again.