I've actually looked into a similar issue in MD. Not licensing a bike, but licensing a custom built motorcycle, which I imagine would be about the same process anyway.
Assuming your state has procedures in place for this sort of thing, it should be fairly straight-forward. I know at least in MD, all you have to do is pass the standard motorcycle safety inspection, and you get a VIN. What I would do if I were you is get the documentation for the tests they perform in the safety inspection (or any other inspection that OR might require for custom vehicles). I'm pretty sure that by law they have to make it publicly available.
For some idea of what you're in for, this is from the MVA website:
How do I title a homemade motorcycle?
A “homemade†motorcycle is a motorcycle that is assembled from new and/or used parts by someone other than a licensed manufacturer.
You can apply for a title in person at the Glen Burnie branch office. Typically, you will need to submit the following documents:
---* Proof of ownership – Proof of ownership is required for the frame, engine and transmission used in building the motorcycle:
------o If the frame, engine and/or transmission is new, the manufacturer's certificate of origin is required.
------o If the frame is from a used vehicle, a title for the vehicle in your name or a title that has been properly assigned to you is required.
------o If the frame is from a salvaged vehicle, a salvage certificate in your name or a certificate that has been properly assigned to you is required.
------o Other documents that may establish ownership are:
------------+ Registration document and bill of sale – ONLY if the state from which the frame was obtained did not issue a title (usually because of the vehicle’s age).
---* Application – You may use either the back of the Maryland title or the Application for Certificate of Title to request the new title (and registration, if applicable). When the Maryland title is used as the application form, complete the section entitled Application for Title and Registration.
---* Proof of purchase price – You must submit the bills of sale and/or receipts for all parts and labor. The MVA may require that your proof of purchase documents be notarized.
---* Odometer disclosure statement - You may use the manufacturer’s certificate of origin or the title to document the mileage of the vehicle. A separate odometer disclosure statement may also be submitted.
---* Application for Assigned Vehicle Identification Number (if applicable) - A new vehicle identification number (VIN) may be assigned to the completed motorcycle. The Maryland State Police will install the new VIN plate after they have inspected it.
---* Motorcycle Equipment Certification - You must certify that the motor has a rating of more than 1.5 brake horsepower and a motor capacity of at least 49cc.
---* Maryland safety inspection certificate - A safety inspection is required if the vehicle is being registered at the same time (most cases).
Your title will be mailed to you. If you also register the vehicle (most cases), your registration card, license plates and expiration date stickers can be provided immediately when you apply in person to the MVA; otherwise, these items also will be mailed to you.
And, the vehicle systems to be inspected on a motorcycle:
• Steering system
• Frame
• Brake system
• Wheels / tires
• Fuel system
• Exhaust system
• Lights
• Electrical system
• Mirrors
• Windshield
• Passenger items (hand hold and foot rest)
• Body items (seat, engine mounts, stand, chain and guard, fenders)
• Speedometer / odometer
So, yeah, like others have mentioned, you'll probably have to have DOT approved wheels and tires, definitely DOT approved lights, and the frame probably has to meet certain strength and design criteria. I haven't gotten around to requesting the appropriate form that would tell me all the details yet (not available online..at least, I can't find it), so idk the details of what you might want to expect, but when I do I'll post it somewhere on here. I imagine they would also want you to have taken certain precautions with the wiring of your power system. Stuff like protection against water, protection in case of a crash, etc.
Yes, a commercial venture to make and market complete conversions for sale is much more applicable to someone doing a one-off than information about licensing custom-built vehicles. 
