working on number two with crocker pups updates will be posted
The fiddle people change standard violin tuning to lots of different ones, but my favorite is deadman - I have no idea why it is called that. Standard fiddle is GDae. Deadman is D'Dad - and they do it with standard strings so that low string is really floppy. It drones along in a really great way. So there is your bass string.
I liked it so much I've tried it on my mandolin, and true enough, lots of fun and gives a nice bottom end to a pretty treble-y instrument. I am likely one of the very few to do it on a mandolin, though, as they are such a PIA to tune in the first place not many are going to monkey with that.
The string isn't fretted at all, as far as I've ever seen. It just adds the low drone, which works for OT type of music. Blues and folk, maybe not so much.
Here is a youtube clip of a guy playing this tuning on a fiddle - very bagpipy the way he does it and likely not for everyone!
and another http://www.box.net/shared/mdg3ofb4rq