I didn't realize that, but it makes sense, especially after seeing the link from PeteyHoudini.
Great link, thanks. I considered a capo, but it interferes a bit with one of the chords I use, and to get close to my vocal range I would need to capo pretty high up. I may end up doing a combo of going with a D tuning, and then using a capo at the 2nd or 3rd fret, which would get me to the key of E or F. Or maybe I'll get bold and try an Eb tuning, and hope I don't pop the bridge.