The issue with not using a flush valve is not having an air gap. I realize the water comes in the top and being what it is, there will never be any water close to it underneath, but washing machines, urnials, and the like are required to have a air gap inlet plumbing. Old urinals have four wing spring loaded turn knobs, or spring loaded push buttons, but they do have the proper air gap installation. I did stumble into a brand new Sloan flush valve out of the box in a pile of Home Depot return stuff that a local salvage place had for sell. They get large crates of returns from Home Depot and then resell the stuff, this just happened to be in there.
Looking on Ebay I just found one complete in the box Sloan urinal flush valve for $75 BIN, another for $79, and finally stumbled onto one for $50, also BIN ($20 shipping however).
Biggest problem is that most Urinals have a back outlet so you need in the wall drain plumbing. A few, from looking at Ebay, have a bottom drain.
Kohler K-5024-T Darfield, but quite expensive at $180.
American Standard 6581.015.020, just over a $100. Oddly the seller of this Am Standard had "more than ten" and "2 sold" and GET THIS...
30 watchers. Never have I seen so many people watching an Ebay ad before............
Charles