I'm a big fan of DADF#AD myself - also play in "Open G" sometimes, and have messed with the tuning that Jimmy Page used on Rain Song as well (just can't remember what it is off the top of my head).
Mind you that was after playing Rain Song for 20 years in standard tuning because that's what the Led Zep songbook told me it was in, complete with pictures. Boy was I pissed off when I found out how he really played it!