I can recommend the Smartwool Microweight T-shirt. I'll admit I've only worn it once crossing Bleaklow and Howden Edge on a hot September's day. The shoulders and parts of the body were wet with sweat/condensation by the time I arrived at the pub BUT I remained comfortable throughout, it didn't smell the next day and I was impressed.
Difficult to get the MICROweight T-shirts. You'll have to go to www.macmountaineering.co.uk to get them. Very nice company. I should know I've just received some of these t-shirts from them.