Wikipedia entry for Gibson Switchmaster.

I acquired this guitar in October 2010 from Music Folk in St. Louis.  They'd had it for over a year, and I kept thinking about it.
It's not really collectible because the previous owner had replaced the pickups and cut a hole in the top to do it(!).
Luckily, he had not discarded the wonderful original P90 pickups. 
The shop restored it to functional wonderfulness but there is the repair, which can be seen up close.
Had to give a 1956 Gibson ES125, an Eastman 803C, and a chunk of cash,
but this guitar is the rest-of-my-life guitar.