It sounds too complicated to me. The ADuC832 is ISP capable, with a laptop you could easily upgrade to new software, BUT For field upgradeability the boss sez, why don't we stick a USB port on there and use a flash card reader (cheap) like the ones to read camera flash memory chips

I think Fritz has a problem, not with technology, but with explaining to his boss. Oh, how often have I been there.

My preferred option is to use a PDA, that is reasonably cheap and, with proper selection, has a serial port.

Erik