> It doesn't look like we can do this anytime soon, because FreeBSD 5.2
> is very far from being as stable as 4.9, as I recently had to find
> out again. Besides, it's also still a good deal slower. 5.x doesn't

May I ask what are the problems related to 5.2 ? 
If I understand correctly, ipfw and dummynet should be quite similar, 
and the same should be true for the other userspace processes.

I'm asking because I was going to start a personal port to 5.2
to see how well it could perform, but perhaps I should ask who
has done it already.

Dave.