A little recognition for the users who have the most contributed to implemented ideas. We can imagine a badge for 1, 5,.... 1000 ideas implemented on the model of likes/ solved, etc.
We love the thought of getting people more engaged, but this can be a slippery slope of users being tied to certain features on community. We love the Idea of appreciating users for submitting ideas, but would like to stay away from animosity on ideas not being implemented.