Does anyone have any pictures or info on what the "official" (read "nintendo-sanctioned") way to develop for the Gameboy Advance? I know many homebrew developers just use a GBA flash cart and various homebrew solutions for it but what is used for the games that end up on the shelves?
I don't know about the Nintendo one but here is the SN Systems one, missing from the picture is the SCSI card.
there are Intelligent System tools/emulator/debugger take a look here http://www.intsys.co.jp/english/tool/index.html
SN Systems tools require that you have proper license to develop for said system. As long as you can provide proper documentation, they will sell you anything. This is because, with all of the experience I have with SN Systems products, all of them required "official" libraries/tools/binaries that Nintendo distributed.