I'm pretty sure Nanjing is behind that whole series - they're all on their site
here.
one of the earliest was a OneStation lookalike called the "Digital Dragon system" with Nice Code games built in and a generic multicart bundled, but they seem to have abandoned the Nice Code stuff entirely now. They all take the same type of carts (same as the FC-3000/OneStation Elite I think - just miniaturised famicom carts) but I've never seen anywhere that actually sells additional carts separately since the FC-3000 itself went out of production.
there's also
this one, the "NJ Pocket" which kind of gives the game away. although that one's 16-bit and it doesn't have a cart slot.[/quote]
And indeed, the GB Station and PVP Station are both listed on Nanjing's site.
But that's not all! Searching for the model number of the NJ Pocket, NJ250A, turned up this:
http://sznanjing.en.made-in-china.com/Which is... exactly what it looks like. An index of products being sold wholesale by Shenzhen Nanjing. This includes the NJ Pocket, the GB Station, and the PVP Station.
They also list several "Arcade Game Stations", which are... interesting. No, they're not Wii clones like the Wow (I'm surprised those
aren't listed on the site, actually)... these are PlayStation 2 lookalikes which can load movies and various consoles' ROMs from a flash card. Sounds very similar to the
GameBox reviewed by TweeterMan... except, y'know, this one's made by Nanjing and looks like an older-generation system.
Apparently some of these portables are based on the 32-bit SP350 chip (Sunplus?), at least if
this Alibaba listing is to be believed.