These have just come out. I bought one, from
www.insight.com for about £60 - not bad!
It works in a Motion LS800 tablet computer (I actually copied 4GB to it) and appears to work in an HP4700 PDA, but fails to work in a Casio EX-S600 and a Pentax DL DSLR.
I was aware that there is an issue with SD over 2GB (the interface and/or the filing system changes; Windoze XP offers only a FAT32 format option on it) but one needs to be careful. Those two cameras are both 2006 versions...