The DS Lite only version has a more compact form on the memory expansion module that's too short to fit in the original DS, but doesn't protrude from the GBA slot in a DS Lite like original GBA carts do. $50 right now through Lik-Sang, either system, free shipping with a special deal they've got going on right now.
wolfwings - 09:26 pm - Not really...
...it's very unlikely they'll add anything to the 'US' release, considering they don't even have to translate it. Opera wrote it multi-lingual to begin with, and it's very little new code. If they figure out how to wedge flash support in, it's more likely they'll release a software update for all versions of the cartridge to enable it.
Remember, the GBA and DS doesn't even have any concept of region coding. It's not like a PS2 or an XBox where they have to modify the code and re-burn the media. If they write it multi-lingual to begin with, like Opera is with this browser, they just change the default settings on the user-recordable cartridge and start shipping them out directly.