You haven't given us the size your shop, but you COULD go with 1/2" copper distribution pipe, unless your shop is HUGE. (Don't get me wrong, for a few dollars more, I'd go with 3/4" too).
I'd use some sort of soft hose between the pipe and the compressor too, to decouple it from the vibration. If you don't, then I'd definitely BRAZE the pipe, instead of solder. The solder may not hold up to the constant vibration of the pipe. I seem to remember that when I was researching a copper system, I wasn't pleased with the percent of safety factor with just soldering (it was rated for enough pressure for the system I planned, but it didn't have that "twice the system pressure" safety factor I prefer in compressed air systems and lifting systems.
I'd put at least a filter at each outlet. This is the little 'glass bowl' thingy. It has a sintered brass filter inside. It does a WONDERFUL job of removing water from the air--as long as you place them far enough away from the compressor. I've tried placing these right at the compressor, but the air is still too warm and able to hold a lot of water. Once you get a few feet from the compressor, the air cools down and these little filters do a great job of taking water out of the compressed air.
You could use a 90-degree fitting to install the filter horizontally.
In the places I work the most, I like to have at least 2 outlets, so I can have 2 tools set up at at the same time. OR, you could build a little manifold to plug in, whenever you want more than one tool ready at a time. (I have both options at my shop...both the compressor and remote outlet have a pipe-fitting manifold with two quick-disconnects each. I also bought a little aluminum manifold block online and have a one-input, 3-output manifold I can attach, when I want more tools working at the same time, or I am visiting someone else's shop).
My other thought is that I was headed in the same direction you are, but now I'm going a little different route with my setup. I think I'd rather have a small number of hose reels, mounted high, than have a lot of outlets, mounted low. A 35- to 50-foot hose reel in each corner can reach just about anywhere you want to go in your shop and doesn't take up critical wall space with outlets, unless you have a HUGE shop. Even in a huge shop, I'd rather have fewer hose reels, mounted higher, than more outlets, mounted lower. Wall space at waist height is at a premium. Higher mounted reels stay out of your way and keep hose off the floor as much as possible.
I wouldn't go straight down into the quick-disconnect coupling. Any moisture you have in the air will go straight into the tool. I'd use a "T" where you show the quick-disconnect, run a filter horizontally off the pipe and add "T's" and elbows to put a couple of quick-disconnects on each filter. Then, run a couple more feet of pipe straight down through the "T", with a tank drain valve at the bottom (either a 'pull ring' style, or the standard valve at the bottom of a compressor tank, a more-expensive ball valve, or an electric-auto-timer-valve, if you really want to go fancy). This will allow a lot of moisture to drop directly into the tubing extension and you can empty the extension daily, while the system is pressurized.
For the price, you may want to look at what RapidAir has. They have a pretty extensive 3/4" piping kit for $200. You'd likely need to add a few components, but I've definitely considered going that route too. You could really get away with their kit with smaller tubing, for about $75, unless you have a humongous shop.
You've got a great start to your planning. Looking forward to pics, whatever you decide to do.
Kev
