Someone mentioned about not finding Sitka in Cabela's or Bass Pro retail stores. Not sure if all Scheels stores carry it, but the ones in Lincoln and Omaha did and had excellent selection. I know Scheels has stores in IA and elsewhere, don't know if anything is close for you.
Ben from Oz, I don't think Sitka wants to make 'normal' cotton clothing for several reasons. However, I think what you're asking is clothing for warm weather and I'd recommend the same things that Larry Yien did: go with the Ascent Pant (last year called the Mountain Pant) and the core tops. The Mountain Pants I had last year dry out amazingly fast when walking through wet grass, etc. Instead of sitting on my stand soaked, I'd notice very quickly my pants were dry. Amazing. I just sat many hours in a warm tent at the Sitka Booth at Compton this past weekend wearing the Sitka core top and never felt sweaty. It does a great job of transporting sweat/moisture to the surface where it is spread out for quick evaporation. And all of it is lighter than cotton.