Special rewards for Challenge Mode

[Daneasaur 420]

As I have been enjoying the offline bots, I've wondered about something special for completing challenge mode beyond experience points, badge points, or achievements.

Perhaps completion of this mode would grant something special, such as the ability to use different weapons as any Jason. As has been shown in the Virtual Cabin, it's flawless to do so. I think this would grant a fair bit of replayability as well as giving the players more reason to pay for kill packs. IE: Using Part 9/6 with the Machete or using part 2/savini with the pig splitter.

Opinions?