there is a script to make the tablet boot up and see the MicroSD as the internal sd Sugsy89 wrote it for the Excel
it basically swaps the two partitions so all downloaded apps go straight to th MSD you could effectively do this and if you needed an external data device could plug a usb stick into the OTG port
you would have to modify your tablet but its doable
read from top of 2nd page here Remember this was done for excel not extreme do not flash anythingjust saying that its possible to do this hack