The Trad on GTH pants:
A word of warning, though. While you can, and should, wear these trousers with a sport coat, they are not to be worn to work. These are occasion trousers and with that comes the responsibility of time and place. The time is summer. The place is near water and within arm’s reach of a G&T. Going sockless helps, and a half lined navy blazer in linen keeps you respectable, while the dash of Ray-Ban aviators kicks you into the classic GTH look. True devil-may-care attire always requires forethought.
The same advice could be said for GTH shorts, though you have more leeway in what to pair them up with – in my case I often go with a white linen button-down or polo shirt sans sport coat.
Where to find: Ralph Lauren, Rugby, and Gant (Rugger or Bastian) are good places to check. Engineered Garments will also usually have a few in its spring/summer collections as well, and from this current season I just received an exceptionally great pair in a red/white/blue floral print.
Now I just have to wait for Seattle to break past its sweltering 68°F summer days before I can start wearing them (line borrowed from a Redhook ad).