[John]

Well, that's the thing - if I made a hack like yours, I'd release it, yet fine tune it and add smaller details that made it unique. Then, on top of that combine it with a unique graphical style that no-one can really copy (unless they rip it, but if their forum becomes popular they're going to get found out).

That way, the hack would be known as yours by everyone, you'd get all of the credit for it. And yet none of the bland and standarised versions of it on the web would be as good. You'd have more members through people knowing more about you and your site, and still have something like no other.

Still, it's your choice.