Last i checked the chromebook memory card or whatever they call it is one with the motherboard so i highly doubt it will be upgradeable at the moment. When/if google gives the go ahead local places like best buy & their Geek Squad might be able to upgrade the memory
I have read several places that its soldered to the motherboard. Can it be expanded? Maybe if you can "piggy-back" on top of the existing ram. Or, de-solder and add a new stick if the mb will support it.
The 2GB memory and the 16GB SSD of the Cr-48 are "permanently" installed. Sometimes it's a challenge to alter the thinking we've often used with Windows or OSX-based computers when considering a completely different approach to a personal computer.
Thus far there hasn't been a compelling reason to upgrade either the SSD or the memory of the systems.