AFAIK the connector is available on digikey and sites like that, so you should have a pretty easy time with that. We also have the connector pinned out in the trimming guide (scroll down to Bluetooth) https://bitbuilt.net/forums/index.php?threads/the-definitive-wii-trimming-guide.198/
BitBuilt - Giving Life to Old Consoles
cheese
Shank
Thanks! I didn't really "prototype" anything, I just kinda wired it to a USB port and it magicaly worked. I'd love to stay in the loop! You may find the compendium useful as well. https://bitbuilt.net/forums/index.php?threads/wii-rvk-01-compendium-released.93/