This shit uses an older cyclone chip I've read which means that you can probably forget about 16 bit cores and up. Pass on this, especially with the insane shipping amount. Very happy with my Mega SG and Super NT though!
Weirdly enough a while ago Kevtris said on AtariAge forums:
"The Pocket will run genesis and SNES cores, so it can play those things, along with the gb/gbc/gba functionality. We are allowing homebrew cores for it, so anything is possible."
But even if that's true I HIGHLY doubt he'll be allowed to 'unofficially' release a new firmware with those different cores, because then where would the market be for their Mega Sg and Super Nt anymore? People could just buy the Pocket + the HDMI Dock then run ALL three systems (and many others) on the Pocket by itself and they would loose sales for their SNES and Genesis devices. This is also the same reasoning (I assume) why there isn't a jailbreak to play Genesis on the Super NT, or play SNES on the Mega Sg – they want to keep things segmented a bit.
Anyway, I'll be getting one pretty much to solely replay those Castlevania GBA games I love, especially when a bone stock (not even upgraded with a nicer quality backlit screen) folding GBA is running like $130+ on ebay, the Pocket really isn't that much more and you get a lot more (plus it's new, not old).