A year or so ago I came across a feature request system where customers could request a product or feature request and vote it.
The system was nice as every customer got three votes that they could assign/unassign to whatever request they liked best.
But this was not a bug tracker. It had a much cleaner and simpler interface than most bug tracking packages out there.
I can't for the life of me remember what site I saw it on or what package it is, does any one know of any package that offers such functionality?
http://www.dreamhost.com have a system like this for feature suggestions - I currently have 55 credits which I can use to vote suggestions up or down; more credits are required for harder problems. Theirs looks to be in-house, but there are a few similar ones listed here: http://mashable.com/2011/03/06/user-feedback-apps/
Of which, I like the look of UserVoice, CrowdSound, and SuggestionBox.