Is anybody building a Conveyor Belt 3D Printer?

Is anybody building a Conveyor Belt 3D Printer? I found a pair of brand that have one model of printer in this style but it seems to me a bit overpriced. Is there some tested project or some community working on it? Is it on chinese clones market something to work on to uprgrade to something working?

At MRRF the developer of POLAR https://polar3d.com/ had a demo unit of his PrinterBelt. Tom did an interview with him (at 0:39 seconds in) https://youtu.be/d6GltNhkvG4?t=39

It sounded like Printrbot is still working on the production version. They did a beta run last spring/summer.