yep, the N800 supports SDHC, so i suspect it can even go 32GB pr slot if the user feels like trying.

basically, the max size given in a manual i usually the max size that the company had at hand to test with at the time of design, not the absolute max that the slot can handle (tho it will get slower as the card gets larger, as the bus will be optimized against the smaller card that they tested).