Big Box Resonator
These guitars used recycled acoustic guitar necks with home-made boxes and cooking pans as resonators. In addition to the resonator pans springs were added to the inside of the boxes to add artificial spring reverb. Drain hole covers were used to cover the sound holes and the darker of the two had a "lipstick" single coil magnetic pickup along with a piezo disk and a selector switch to blend the two.
Starting these builds was pretty straight forward. Start with the neck, and the pan and build the body around that. The boxes were built using pine 1x4's and the front and back used 1/4in plywood. The resonators were spring-form pans or other cooking pans which had a nice resonance to them.
It might look messy in there, but those springs did wonders for the sustain and reverb!