You probably won't find much cotton out there. But there is a ton of technical wool products from Ibex, Smartwool, Rapha, Icebreaker, etc.... Just do searches on wool jerseys. They wick better than cotton and can be quite a bit more comfortable depending on the quality (cheap wool is scratchy)
the ever shifting stable loaded with comfortable road bikes and city and winter bikes
Canari has some mos' excellent wool jerseys in their lineup this summer.
thin, lightweight, wick well and no-itch. feel like cotton, 65-70 bucks retail. AND high vis colors.
this will sound odd only to those that haven't worn the modern summerweight wool clothing yet, but I pull on a lightweight Smartwool T-shirt or these Canari jerseys, and they actually have a COOLING effect.
order from your local shop that carries Canari jerseys if they don't stock the wool ones.
Cotton T-shirts, about six bucks at Mervyn's. Don't believe everything you read about soaking up sweat and making you miserable. I haven't worn polyester in about 10 years--I wear either a T-shirt or a wool jersey (I got two for half-price from Rivendell).