Firstly Bill >>> u've got every right to feel (kinda?) pissed, mate....that really sucks when a/holes damage ur ride, and then don't even have the decency to leave a note with their contact details for insurance purposes!
Secondly >>> I personally would be going on a HUNTING mission, and I wouldn't cease until I have exhausted EVERY possible avenue!
Are there ANY CCTV camera's positioned anywhere near where u park ur bike that may give u a clue as to the IDENTITY of this morally-bankrupt individual???
Is there any paint residue at all from another vehicle left on ur bike??? (there is a chance that the person responsible may need to park in this area on a daily or semi-regular basis....definately worth keeping an eye out for!)
Any witnesses??? (A poster with a pic of ur bike and some incident and contact details left somewhere close to the incident area may encourage a witness to come forward and provide u with enough info to track down this piece of scum)
Lastly, only if all the above does not help bring the responsible party forward....I would be making a claim on my own insurance (...is the damage worth making a claim, re: excess???)
Good luck....let us know how u go with it,