Ok, I am wondering whether or not, using the correct settings and hardware, it would be possible to have a Mario Kart Double Dash LAN Party with a PC and a real GameCube using the Broadband Adapter. Is it just not incompatible or would there be some trick to make it work?
It should be possible, I think. It's been ages since BBA support was added, but I remember some people reporting that Double Dash was working between Dolphin and real GameCubes. Furthermore, I'm pretty sure I heard that Dolphin's BBA support works with Phantasy Star Online and custom servers. So it should work. Any hurdles you face are probably going to be network related, but I'm not certain it requires anything special for LAN play.
It supposedly works. Gotta keep dolphin full speed though
I've done this before and can confirm it works. Played for a couple hours. No problems!
Dolphin works with PSO, but an online game is much more forgiving of latency and in-game slowdowns than a LAN game would probably be.