Either that or really busy.
Like I said in that other thread, I'm not really expecting this plug-in to actually get made, but it would be pretty cool if it did.
Maybe it could be done in collaboration with one, or both, of the people who made those flash based ones??? Considering the copyright, some form of contact with the original creator would be necessary...
In fact... My guess is they've been contacted before about integration into other programs... But who knows, maybe the original creator would be up for the idea of a paint.net plug-in.