@4spdragtop was correct. There are a bunch more out there doing basically the same thing. The one I posted did it the cheapest way (I liked that) and covered what I needed for mine.
Besides the metering valve, I dropped the inside grate down for more room (handy for wheels), made the glass easier to change and now have a dedicated vacuum to collect the dust.
A few years ago, I did a mod with a flood light in the corner to replace the fluorescent light mine came with. That was a great improvement too. It just uses a water resistant type flood light fixture that seals the bulb to the socket.