damn....

anyway, measured the voltage, and it's deffinatley 5v.

Edit, looking at the card, the traces from the flash chip seem to run straight to the sil chip, so it could just be as simple as the 5v varient of the chip will still work fine when the data lines are run at 3.3, and the solution for the PC cards would be to just use the 3.3v chip and put a regulator on the vcc pin of the flash chip