New bike...smacked by a car...any advice appreciated

Too easy to be accused of carrying a concealed weapon.
Wear the katana across your back, they'll get the idea.
What's the big katana called, dai-katana? ;-)
For visual effect, a sheathed bokken would probably suffice.
Mitch.

Or how about a full-length Indonesian machete mounted on your bike?
have a look at techtip 16 for how to mount it:
http://www.wildasia.net/main/article.cfm?articleID=97

flaps.