While you're listing exhausts you will almost certainly never see in the wild don't forget the
Area P which was produced for just a year or so for the Pre-Gen bikes.
I have one on my 2005 EX250. The quality of this pipe is the absolute best I've seen, perfect fit and finish, beautiful welds, and it's aging quite well on my bike.
And Area P was a great company to deal with, the main guy was Kerry Bryant who is a very nice person.
http://areapnolimits.com/products/Sl...Ninja-1988.php