Here is my new DIY free motion system w/ Kreitler 3.0 rollers. I've only used it for about an hour so far but it works well. It uses a minimalist / lightweight track system with 1 inch PVC pipe cut in half with a bandsaw, and roller blade wheels. This is for hard floors only...if using on soft floors I would put a board under each track. When you put weight on it, the pipe stays in place on the floor. The blocks of wood attached to the pipe keep it from rotating and serve as attachment points for the surgical latex tubing. The tubing is terminated with sections of BIC pen and 100 lb fishing line, and (on the frame end) big fish hooks with the barbs sawed off. The brackets for the front wheel guide rollers are made from a block of ABS plastic (I tried wood at first but it split). I will probably replace the blocks of wood attached to the PVC with plastic also, to avoid splitting if stepped on. But, you get the idea.