Things I ponder: Knowing it takes multiple transceivers and that it is based on the 802.11g means I doubt there will be any n cards that are 802.11a compatible. It wouldn't be worth it to have the extra transmit capabilities built in to the transceivers.
Actually, 802.11n and 802.11a are compatible, but vendors may not make them that way. The 802.11n standard supports both 2.4GHz (b/g compatible) as well as 5GHz(a compatible) but I think the majority of vendors are sticking to 2.4GHz since 802.11a never really caught on. Still, with some hunting you might find a forward-thinking vendor that has both 2.4GHz and 5GHz support.
Oh, and Welcome to LQ!