I was wondering about a scale model too the other day, as I like to build them, but I was considering using it as a test bed for painting schemes..before I did full scale. The closest I've found so far is the Yamaha Virago XV1000 at 1/12th scale. Here's a link to it:

http://www.hobbylinc.com/htm/tam/tam14044.htm

It probably won't remind you too much of the Vulcan though, except for style..engine is way diff than ours. The only other one that's close is the one Mazdaracer posted.