I believe it would be a nice idea, or atleast a moderately decent one, to use flattr on the forums.
I'm not thinking of anything too fancy, something like a flattr button where the skype button is right now, basically if you have flattr you could opt to put it in here. I also think it would have to be something official for it to function properly, like a post that explains a bit about flattr and what it is, and how to use it, because otherwise the user base of it on these forums would be so low it would almost be pointless to have it.
Anyway, basically it's a microdonation system that's easily integrated into just about anything.
Imagine you putting in $5 on your flattr account every month. You see an awesome script, or a post and see that the guy has flattr. Well, you press the button and then at the end of each month, the $5 that you put in is divided amongst all the clicks you made. Say you made 5 clicks, all of those 5 would get $1.
It's not alot but it's something, and it would give more incentive while being more attractive than asking for donations.
http://flattr.com/