Columbia sportswear makes long sleeve sunblock/cool pullovers. You can get the shoulder pads sewn in. Sizing varies so you have to try them on. They have a light tan color that I like, and are made of stretch material that lasts for years.
I have purchased several of Jim's shirts. They are quality and the service is great. Several of my shooting friends wear his shirts. If you need a special logo he will do them for you. I plan on getting several more shirts from him this year.
I like the Pine Tree, T-shirts. They're cheap, so I don't expect a lot, but they seem to hold up 3 seasons or so before the neck loses it's elasticity.
I've also had good luck, believe it or not, on e-bay. It's kind of fun looking for bargains.