I'm in the process of setting mine up, so I can give you my thoughts rather than proven ideas. I plan to use 2 brass valves (hot and cold) join them together and into a filter. After the filter I'll have an inline thermometer. After the thermometer, I'll distribute to right and left side of my 6 ft sink (I have a "regular" faucet mounted in the center of the sink for non-critical stuff). I'll use a brass valve with male hose fitting to turn water off and on to each of the 2 outputs. I'll use a nylon barb adapter and have 3/8" ID hose available for each.
I'll be using copper and brass fittings. I use the type of brass valves with rubber washers (yes, they'll need to be replaced every few years) as opposed to gate valves as they give finer control. I use the 2 brass values rather than a shower valve. My feeling is that shower valves, unless very good (and expensive ones) don't seem to give a fine enough control over temp. On the other hand, shower valves are often pressure compensated so might be better if your water pressure fluctuates when someone flushes the toilet or turns on cold water.
I have a "master" full port ball valve on each line that shuts off all water.
I put the thermometer after the filter and close to the output valves so it will read as close as possible to the output temp. But still easy to read with one hand on the hot and cold valves. I'm on well water, so I'll install a 5 micron particulate filter (I have a whole house filter, so this is probably redundant).
I thought about a used Wing Lynch unit that was available locally. But it had been pulled from a pro darkroom a while ago and I could not be sure it would work. I don't think it's economical to repair those.
Here's a picture of the Delta commercial unit: Dead Link Removed
There is another unit I've seen that does use a shower valve. It's about US$100. Can't find the link to it right now.