I know this post is months old, but I second this. Seriously, this thirteen year old title is going on Amazon with the mic for over $40. Some people have been saying they bought a Dreamcast and a mic just to try it out. People still want this game, and it sucks that no DC emulator has a mic plugin. I've been looking for a few hours and was interested years ago, and it looks like other people have been looking for years. It's not the greatest game in the world, but it's really interesting to people and there are some really popular YouTube videos of hilarious moments in the game. This is forgetting about the other titles that need or warrant use of the mic.
It wasn't the greatest DC accessory, but come on; Dreamcast emulation isn't complete without it. Could someone at least try to code this? You'd be a freaking hero.