number of years ago, I made a grass seed striper, basically a big brush that sweeps the grass and knocks the seed off and into a box,
I read a post similar to this one so I took it out and tried it on wheat, and as far as stripping the seed off, it did a great job, the problem was that a lot of heads and white caps (part of the head still covered the wheat berry and it need cleaning
I never tried it but my thought was if I want to continue this process to take two tire, (like on a garden tractor rear end, and space them so the treads touched, but put sprockets on them and run them with a few RP Ms difference, say a 40 tooth sprocket and a 36 tooth sprocket, (maybe smaller, most likely have to go by trial and error to find the correct ratio) and by air pressure one could adjust the pressure in the tires to get the proper pressure, or one could spring load one side,
any way then feed the raw wheat and threshing through the tires basically hulling it, as it would be spun going through the tires,
and then I think the product that come out of that would be able to cleaned on a fanning mill or a winnowed, with reasonable ease,
most grass seed brush strippers are usually fairly narrow, mine is 8' wide but many are only 4 foot, some use sidewalk brushes, mine used weed eater twine, and one can see I only have 4 vanes it does not need a lot of bristles,
as one can see in the Drawing the brush sweeps off the seeds and puts them in a box, I used window screen to let the air out,
but a unit just a few feet wide would do for an acer or less and could be pulled with a lawn tractor or ATV, there is a before and after picture of the wheat,
and a picture of the product in the box, there are a lot of berries in the bottom of the box,
my guess is the product off the stationary chinese type thresher, would not be much better than the product off the seed stripper,