Tommy Crawford bought all the old Bassani two stroke tooling and is making pipes:
T.C. Exhausts
(909) 658-4205
1126 Navarre Drive
Hemet, CA 92543
He was getting $350 for a 3 to 1 pipe quite a few years ago so I don't know what he charges now.
Jemco might be able to make a 3 to 1 as well
Jemco Racing Exhaust
(713) 461-3834
1919 Blalock Road #B
Houston, TX 77080
Geeto is correct about a 3 to 1 pipe killing the powerband. Your midrange will be fine or even a little fatter so if you live in a city and plan on using the bike for stoplight to stoplight runs, go for a 3 to 1. If you ever plan on running on a highway and would like to be able to get past 65-70, you may want to think about some 3 to 3 chambers.
Jim