Originally posted by SilverWind:

-No damage
+On hit: Marked for death for 10 seconds

In other words, a Jarate SMG.

Thats a bit too much, the jarate has a long cooldown, thats why the amount of "marked for death"
I would say:
+On-hit: Marked for death and slowdown for 5 sec.
-90% damege penalty

How about instead of Jarate, it outlines the enemy that was shot, allowing you to track whomever you shot if they decide to run away, I.E. a Spy who decided that this Sniper was a bit quick on the uptake this time and wants to come back later.

No damage, or at least minimal damage, and a smaller clip. the Paint can wear off after.. 15 seconds?

This will allow snipers to be able to paint targets and track them for a short period of time and line up shots where they couldn't before.

Originally posted by Rockabunny:

How about instead of Jarate, it outlines the enemy that was shot, allowing you to track whomever you shot if they decide to run away, I.E. a Spy who decided that this Sniper was a bit quick on the uptake this time and wants to come back later.

No damage, or at least minimal damage, and a smaller clip. the Paint can wear off after.. 15 seconds?

This will allow snipers to be able to paint targets and track them for a short period of time and line up shots where they couldn't before.

I like the marking idea. Have a large clip but downside of very little damage like even less then the carbine. Would be good for team mates too assisting or pointing out a enemy in the back row that may of snuck back.