I'm pretty clueless about how an automatic drawbar works and don't know of a source for frameless motors either but kind of wanted to say that if your having a big problem locating a component like that, that seems pretty central to the design, maybe you need to change the design. Don't most automatic drawbars just use a belt and pulley on a traditional motor? I think thats the way our Bridgeport is set up but like I said I'm kinda clueless there. Hope you don't find this post offensive. Just wanted to help.