I worked in a company some 15 years ago that had a similar concept in 2d. I believe the machine is still in operation. The machine manufactured sail cloth with carbon fibre and kevlar. The main difference is obviously that this was 2d however that difference is only a matter of layers. One concept worth investigating however is that this system ran the fibers through a bath/hopper of resin. The resin coated the fibers and then laid them down onto the surface. In 2d the curing process is not much of an issue as you have time and the fibers aren't going anywhere but in 3d this might be a bit trickier.