I made one and stuck it in a box.
The accumulator/cylinder was a bit of an issue, gas cylinders and extinguishers have an odd thread and I couldn't find any fittings to mate with it. In the end I just drilled through the middle of the valve assembly and ran a 3/8th tap through it as I could easily find fittings for that. It worked pretty well as the extinguisher had a nice rubber O-ring on the valve head, something from the plumbing shop would have missed that.
I haven't gone the braided line to the accumulator as I haven't found I've needed it yet. Where the air comes out of the compressor I have a non-return valve, brass 4 way fitting, brass 3 way fitting, pressure switch, barbed connector, relief valve and a stainless Nitto fitting. That adds up to a fair lump of metal that works as an effective heat sink.
I also didn't add the drain tap as I don't use it enough to produce a lot of condensation, after all, its not a workshop compressor and I'm not painting.
I also added an inline tap at the end of the silicone air hose, so in between tyres you can turn it off and let the pressure tank top out at 115psi and give the compressor a rest for a bit. I think it makes a bit of a difference.