Wow, you guys are pricks. Did any of you stop to think that maybe Luc's GoPro isn't stock and that's why he's pricing it so high?
Luc R, I think $310-400 is a good price for a used GoPro. It doesn't matter what new ones go for. All that matters is you have a rare and hard-to-find device that a lot of people on a lot of forums are talking about. Can you please post pictures of your mods? Let us know if you put on little "No Fear" stickers. Maybe little chrome spinners (perhaps 0.5" or better yet 1" )?
Anyway, if you don't have luck here (this forum is full of arseholes) you may want to put it up on eBay. Set the reserve to $480, with an opening bid of $420. Then just sit back and watch the bids pile up! You may be able to sell it for $500 in no time!
Good luck, man!