I was asked to take a look at your posting. I'm a US citizen and we own property in Canada where we park our Sunline for 6 months at a time. They simply "log us in" on a form (no charge) and after 6 months, we take ourSunline back over the border into the US. We could pay the Canadian taxes on it and leave it their permanently on our property, but choose not to.
What I did do was to contact my Canadian Border Crossing and explained your situation. She did have a few questions as to where your permanent residency was, etc. as there are varied rules for varied situations. Either way, I did explain Sunline Co. was defunct and she recommended you contact their Border Agency that maybe off assistance to you. The toll free number in the US or Canada is: 888-848-8240 They also have a web site, it is: www.cbsa.gc.ca
They should be able to assit you.