OK, I'm hoping the folks on this board can help us.

We're looking for a GOOD quality, long sleeved, medium weight cotton, perferably two pockets with NO flaps, in solid colors, shirt. Not a heavy Pendelton type but good quality. It will be used in a business setting (as a type of uniform) with average temps of 50 - 70F. Not stuck on it being cotton but that is the type of look we want.

Any reliable source is welcome.

Why not go to llbean.com and see if they have the kind of medium weight shirt you're looking for?

Not the cheapest, but excellent quality for the money.

Dickies, are really not just for gangbangers any more
Dickies

Eddie Bauer makes nice long-sleeved cotton shirts, they cost about $8 at any of their outlet shops, in a variety of colors. They wear well too. My wife actually likes the feel of them, strokes me when I'm wearing one (may or may not work out for your employees).

Duluth Trading Post

and check out their fire hose pants too.

I don't have any particular source but my preference is for a thinner, tighter weave with a significant amount of polyester in the cloth. With a tight weave it will block the sun and wind and still breath. The poly helps it wear a long time and prevents catastrophic tears. Rip-stop is good if you go 100% cotton but a bit of poly works as well and helps the cloth dry faster.

If you treat a tight weave cotton-blend cloth with a durable water repellent, DWR, from Nikwax or similar it will shed a good bit of rain without feeling stiff or scratchy, and it will still breath. There are some very tightly woven cotton cloths that are virtually waterproof because the threads swell as they get damp but products that incorporate such specialized cloth are pricey. IMO you can do about as well for less.

Online shops like Duluth Trading and LLBean are good but you can often find suitable shirts at Sears, Target, discount stores and second-hand shops. Often the best buy is a $17 dress shirt. Buy them a little loose and you can wear it as a light jacket to block the wind and wear a poly thermal or Henley and tee underneath. With nothing underneath the thin but tight cloth keeps the sun and bugs off and it can be worn sleeves down and buttoned up without overheating.

x2 on the dickies. They are almost the standard when it comes to uniform shirts. They come in 100% cotton and 65/35 cotton/poly which are more durable and maintenance free. If it's for a uniform that will be worn everyday, I'd go with the poly cotton. Cotton shows wear and wrinkles easily. I've used one of their long sleeve premium industrial work shirts for years now as a hiking/working around the house shirt, and it still looks new.

You can find them in any walmart and target it a wide range of sizes, and quite a few discount clothing stores sell them. Cost is about $20, maybe a couple dollars more for X-Tall and 2X-4X sizes.

Cabelas has simple, decent quality shirts:

http://www.cabelas.com/cabelas/en/templa...&hasJS=true

Duluth Trading is good, too.

Check out your local second hand stores and garage sales.

I never have much luck shopping in these places due to my size 6'1" and over 250# or a size 20" neck and 36" sleeve.
However, if you are a "normal" size you can find great deals on lightly used clothing in these places that still have plenty of life left in them.
You will be surprised at the name brand clothing that you can find in these places.