Hi, sounds like your after the same info as me, I've been looking and not had any luck so far. Membership of the SD Card Association is $1500 US minimum. I'm not able to afford that :(
So, if you find anything at all on the SD spec's, please pass the info on, and I'll do likewise.
Oh, the pinout, and a lot of other information, is available in the SD Associations sample specification (you have to join to get access to the rest of them) at :