"I know some Everdrives allow for save states, but as far as I'm concerned this is Magic, and not implemented on the GBA.)"
It's not magic, but it's also not 'emulation' either... It's apparently making a real time snapshot of whatever is going on in the game, and then saves it to system's ram memory. I don't know how its done but maybe it requires some extra chips on board the everdrive?
It's also apparently volatile as in its only available while the system is running, from what I've read. But it maybe able to save it if you push 'reboot' on the system itself as in the case with the N8? If you push power however, its lost. It's ram save.
There are other flashcart brands that also offer real time save state features, or other tweaks such as slow down, or 10 second rewind, that are not using emulation. But they are also using hardware on the flashcart as well as far as I know. For example the DSTwo + uses its onboard CPU and memory to process all the extra features as far as I know.
However, most if not all GBA flashcarts do not offer 'save states' yet, as far as I now. You'll be hard pressed to find one that has an RTC built in, as much compatibility as the X5 has, or the amount of memory onboard for loading up larger roms, or even use microSDs allowing for huge library on the flashcart at once.
The only features that some of the older flashcarts have over the new ones is NOR memory that allowed a single game to be copied to the NOR, and then would load up on a regular GBA without having to go through the menus. Only reason this was useful is for a few games that had cross-link features with DS games, that would unlock features in the DS games. Only if it was detecting a 'header' of the game.http://krikzz.com/forum/index.php?topic=5842.0