My husband's best friend extended his 636...but I think he had a local shop in Daytona do it...not sure if they even have a website. Here's a pic of his bike. I think roaringtoyz also makes a swingarm extension for the 636 pretty expensive though. Check out this link and scroll down to the Kawi section.

http://www.roaringtoyz.com/ExtendSwi...mainSwing.html