DynoMax Bullet Mufflers
I know they're not bullet mufflers, but I have the Dynomax Super Turbos. Mine might have the inlet and exit on the same end but I think the others still sound the same.
http://www.youtube.com/watch?v=DylKXYZ-oUc
They really aren't terribly loud even with side exit. if you had rear exit exhaust they'd probably be pretty quiet.