It looks like they are supposed to pop down and not into a diaper cover. Looks a lot like the design of Bumgenius's microfiber inserts but don't think they make a hemp version. I have thried Google but it did not help.
There are soooooo many nappy makers - particularly in the States so it is probably from some small maker somewhere however it doesn't really matter if you can't find that exact one as you now know that you like hemp and that it works for you so you can find something similar!
I can't let go of this maybe Rump a Rooz would do the trick for you? They make a hemp insert that I have really liked it can be foldes and there is an extra small insert that can be added or used for newborn on its own