Something like the following...
The first vote kick in a run is free.
The second vote kick costs 25g per person voting.
If the target of the vote is kicked, they get the gold.
Third vote kick costs 50g per person voting.
Fourth costs 75g per person.
Each boss that you've cleared in the instance raises the cost to vote kick by 25%. Done four bosess, kicked three people and want to kick a fourth? That'll be 150g per person voting going into the pot.
Each wipe reduces the cost by 25%. Wipe four times, and you're back to a zero cost vote kick.
The only thing that keeps me from thinking this is an awesome idea is that you'd potentially get people farming instances, being jerks just to get kicked and get a gold reward.