J-Lock Spine, Plastic strip for mounting Canvas
I just wanted to post my experience and hope it helps others. I have a 2007 Trail Cruiser C21RBH and had the plastic strip (J-Lock Spine) on the fold out bed split. After several phone calls and emails I found a company called Top Stitch.Inc that not only sells the material but will also do the repair. They charge, as of 6/11/2015, $68.50 per end plus shipping. They also replace screens at $58.50 for the front large scree. I for one do not think that is too bad a deal.
I hope this helps.