So, maybe a deeper rout in the switch area and an option for a battery box cavity rout? We'd have to pick a standard battery box for the rout idea to work.

Gotoh make a good robust one that I'd be happy with, but it's for a sideways mounting battery so quite deep (but relatively narrow). The shallower flat mounting battery boxes I've come across so far are all cheap things with less than ideal battery connections, though someone else may have found a better flat type than I have.