If there is a public project in VT that we are unable to file a lien on and the customer on the job refuses to provide a copy of the payment bond, what resources/databases are available to locate or find bonds?
I'm not sure that there's a database or anything like that to locate payment bonds on public projects. And, after a quick review, I didn't see any statutory mechanism requiring a contractor to produce a copy of the bond. Granted, a Vermont construction lawyer might be more knowledgeable on the subject: Top Vermont Construction Lawyers.
However, it could still be fruitul to request a copy of the bond from the public entity or owner of the project. They may be willing to provide a copy of the bond, especially if you let them know you'll simply request a copy via Freedom of Information Act (FOIA) request if they refuse. Plus, if the public agency does refuse, then requesting via FOIA request is a good option, as Levelset discusses here: Getting a Copy of the Payment Bond | Freedom of Information Act. The National Freedom of Information Coalition actually has a sample form available here: Vermont Sample FOIA Request.