[JeffreyAK]

I've been using 3 lately, the first on my S18 and the next two on my S12, all low-high.

1) Main DADADE, bass FF#GABC (all tuned down one half-step, which would be a half-step higher than your CGCGCD).
2) Main DADGCE, bass EFGABC.
3) Main DAFGCE, bass FGABfBC (all tuned down one half-step).

I've played with DADGAD as well, but not lately. I forget what the bass tunings were, but I do change bass tunings from time to time even with the same main guitar tuning.

{Edit, just in case it's not clear, I don't tune to the notes listed in (1) and (3), I tune a half-step down from these notes. It's just easier to write these than deal with all the sharps and flats! These are what I would tune to if I wasn't worried, in those two cases, about putting too much tension on the guitar and on some of the strings}