There's a pic on this pdf : http://develop.scee.net/files/presentations/acgirussia/Hardware_Overview_ACGI_09.pdf And there some info there : http://develop.scee.net/files/prese...012-Jordan Game Summit-PlayStation Mobile.pdf
There really isn't a 'PSPGo Dev Kit', it's just a different controller for the existing DevKit. Like the DTP-H200 controller for the PSP Slim...
That's right, you just plug another controller to the PSP to the kit, but actually I am not even aware of developers who really bought a 300$ controller to have it look like a Go lol.
Yeah, the only time I ever saw them was in Sony's booth at E3... Don't think I saw any other game studios that had them.