I have a socket CF bluetooth card, and that is just what I do with it. It doesn't stick out of the slot at all, so I just leave it in 24x7, unless I swap it with my Wifi or LAN card.
I did this under Cacko ROM and do it now under pdaXrom.
Most of the ROM's shut off the CF cards during suspend anyway, so basically the card is "disconnected" from the OS during suspend anyway.