I am a Maine resident and this state allows anyone, individuals or companies, register their trailer here (homemade trailers too). The Maine Bureau of Motor Vehicles currently has 13 authorized Statutory Resident Agent companies. In order for someone to register their trailer in Maine, they need an address. Maine's law allows these agents to use their address as the non-residents legal address. Registration periods are from 1-25 years in length more than 12 years having special requirments. Also, if you are a resident of Maine, you can also use the long term plates that the local city halls / tow offices due not offer. Maine residents need to use an Agent as well to get registration lengths of 5 or more years. Most non-residents are not required to pay sales / use tax, but there are circumstances that may require it. Maine also requires titles on trailer, but only if they are 1995 or newer and weight more than 3000lbs unloaded. I would suggest checking out www.acetrailerreg.com and giving them a call. They will cater to anyone, whether they have 1 trailer of thousands of trailers and will complete all of the required paperwork for Maine in order to obtain a trailer plate.