[JohnKacz]

Or give the diamond supporters the ability to vote on features. That may not be something Jon and Will would want though.

[yoodenvranx]

That is exactly what I would avoid. Don't add any special features to it (vote for features, faster support responses) because that will take time from normal development. Just clearly state: "This software cost x$. And if you love it so much that you would pay double the price then you are free to do so."