You can get some fairly small SD to USB adapters, so I should be able to use some of my SD cards as extra internal storage, of course, you could always copy the OS to a shiny new (or old) 32GB SD card and increase storage that way. And upgrade later to 64GB if needed, much cheaper and quicker than waiting for microSD.

Taking some cues from the EEE crowd, small USB hubs should be easy to add. I'll bet you could even add an extra battery in the screen (if you didn't want to take the keyboard), or even an extra one in the keyboard.

If the keyboard does use a USB port, I'll bet you could hack it to run off of a hub instead, and add extra ports/storage in the keyboard. Actually that doesn't sound like a bad idea at all.