I have a Columbia Insect Shield shirt that supposedly works - I haven't actively noticed any bites when I'm wearing it, although I did watch a lady bug land on the brand lettering on my shoulder one day.

But I have used Sawyer's various repellents with pretty good luck. They do have a gear-safe permethrin spray that works well on camping gear. I like their picaridin formula since it has less alcohol, which means your skin doesn't dry out as much and absorb the DEET. From what I've heard, their bug repellant lotion is supposed to be the best form of application, since it stays on top of your skin (rather than being absorbed like sprays and other alcohol-rich alternatives) and is spread more evenly. Lotions tend to have one of the longest retention rates also, so you shouldn't need to reapply as often.