Re:Haystack Onion slicer
By haystack, I assume that you're speaking of breaded, spiral cut onions or the breaded, compressed bricks of the same. Taking into consideration that an onion is a laminate and not a solid vegetable like a potato, what ever this is, it has to cut all the laminates simultaneously along a time axis to create an independent spiral of each laminate. Essentially, you must be turning an onion face into into a slit that can be possibly adjusted for thickness. That would be the same as a potato ribbon fry cutter as you suggest.