I have a 6-string bluegrass Banjo tuning that I implemented on a Dean 6-string banjitar.
It's open-G with an "e": "geDGBD".
I use a 5th-string capo to get the high-G on string-6. This string is an open D (same as string-1), then capo'd at fret-5 to an open high-g.
I have an open high-e (a .010 guage string) in the string 5 position (having this note opens up alot of cool scales and altered chords).
So most songs that are in E, like LLR, I re-tab them in D, because D is the lowest note on the banjo.
I know it's called open-G, but I think of it more as Open-D (I guess I think of guitar as an open-E tuning... the lowest open note).
I do the Allman Bros "Mellissa" in D, and it lays out real nice on banjo.
My daughter calls it a Ban-Jane when she picks it up. I'm calling it a "JamBo" from here on out!
It "is"
fun as "Hell"

.
Oh Yeah, you can play along with all the Jerry OAITW stuff on it too.
I use a set of electric guitar .010's Elixers on this Banjo. It has three .010's on it on strings 1,5, and 6!
Here's the 5th string Capo (which I also have used to turn a Tele intro a 6 string electric Banjo):
http://www.thesuspendercapo.com/