Here are a couple photos and a detailed set of blueprints for duplicating a crimper roller built here in Quebec by my neighbours. The research project that brought it to life and paid the draftsperson were all run on public funds so I suggest that it's open to duplication. I can probably find out the exact status of the license on the blueprints if someone wants to know.
I was lucky enough to inherit one of the 5' wide "wings" of the larger unit when it was split up to share the wealth. I made a simple drawbar hitch out of a scrap I-beam that was lying around and have been using it for about 3 years with pretty good success. I use it on cereal rye with red and sweet clover undersown (fall seeding) and crimp at flowering. The rye makes a great mulch and the clover eventually grows up through it. I give the clover until mid August then mow, spread manure and plow with a moldboard plow. Sections prepared in this manner have the nicest soil texture on the farm the following year.
I have had inconclusive results crimping oats, common vetch and maybe a couple other things. Even if I only use it for rye it's so fabulous that I'm happy with that.
One benefit of this design is that it doesn't require a front implement hitch.