x3i only uses secure digital, but from what i have found so far on ebay they are all for the CF slot which is only avaliable on the axim5. With the pcmcia i can get a 2-5gb hdd for less than 100 dollars.
wow, where are you picking up 2-5gb for less then 100?
as far as i know there are no sd/io to pcmcia cards available.
if you wait a while longer, there is however a hard drive that is coming out with bluetooth/wifi capabilities built in... with an sd/io wifi card or bluetooth you could access the hd wirelessly.