I'd be willing to trade or buy Sonic Adventure 2 battle for the Gamecube. Give me an offer, as I'm not entirely sure how much I'd spend. I'd much more wish to trade, however.
Check my thread. I'm selling it if you're interested. I need to double check and see what condition it's in. I don't remember whether it had the manual or not, tbh.
What region are you in? If you're looking for a PAL disc, I'd be willing to sell mine... you might not be so willing to buy it after you see its condition though. It does work, though, I promise!