A couple of ideas to consider future additions to the kit line-up ...

1. Resonator Guitar - all metal body (rather than wooden body) no pick-ups, just the resonator cone.

... and ... (I know I'll cop some flak for this suggestion but I also know Adam will appreciate it! )

2. Banjo - traditional 5-string "bluegrass" resonator-back type (rather than the open-back "Dixieland" type)

... ok, you can all stop laughing now!