You said you were up for ideas with this mod so I thought i'd mention mine:

I enjoy punishment more, so here are my ideas:

Once the player hits a certain kill streak, he starts taking 25%, 50%, 75%, up to possibly 100% of the damage he causes other players. Making it more difficult to continue on his kill streak. However, once he reaches (whatever number) then there is finally a big (customized) reward.

Let me know what you think!

That requires changing their damage output (not just trigging an event).  I worry about the complexity and load of tracking this per player and having the hook fire on each attack to adjust their damage.  It is an intersting idea, but out of scope for now.