After rummaging around on the Steam forums (I know, I know, but if you look past the retards there’s some good stuff on there) I've found my top 3 ideas, alternatively titled "The Best of a Bad Lot"
Ricochet Rifle Basically, it would fire a frisbee like object that can bounce 2 or 3 times off of objects to hit their targets. This gun is made for levels that are constricted, or levels that have lots of sentry guns that cover area's where a scout would not be able to be maneuverable. Here are some pointers of the gun.
Deals more damage with each Bounce before hitting its target. Ideally, it should do 50 damage, with 50 more damage added with each bounce for a total of 200 damage if all the bounces are used up and you manage to hit the target.
Cannot Crit
Very low ammo before reload (Lower than the scattergun)
Projectile Speed is about that of a Flaregun.
Can be Air-Blasted
Ok, it needs tweaking, but if you make it so that you can only have 1 in play at a time and change the damage increase after bounce to 20 instead of 50, I think its pretty workable. Plus, how cool would it be to airblast one back and nail a scout with his own frizbee!?!
Shattergun was a close second.
Secondary Contender.
Fave for the secondary was the
Splattergun. Solves the sentry gun problem and makes me laugh at the same time

.
Melee Contender
Either the rubber bat (slower swing, less damage, secondary bounces stickies/rockets) or the wooden bat (slower swing, more damage, secondary can charge and send people across the map). These are the most 2 common, if you can't find a thread there without one of these in it, I'll be impressed!
Now I feel like my face is about to cave in from all the trolling through so many many (many) stupid stupid threads; summed up quite nicely by
this.
*sigh* Back to work
