Remember the edelkrone WING? It is an innovative rail-less slider that lets your camera travel four times its own size. edelkrone has announced 2 new models. Wing7 and Wing15 are optimized for DLSRs and heaver production cameras. Wing moves with your camera and stays out of the frame at all times.
This is not a motorized solution but offers a smooth performance. Wing15 has a max camera load capacity of 15lb. You can find out about Wing’s various models here.