It's very simple, actually. The higher you cut, the lighter they get. You're welcome!
Edit: [removed incredibly disturbing pic of hairy man in mid-cheek jean cut-offs. Now, only Roger's eyes will have that burned into the retinas! Hmmm. Maybe I'll repost in a thread about chafing]
Seriously, any running shorts (Saucony, Brooks, Pearl Izumi, etc) like the MH Refueler should be fine. Nice too that you can often find running shorts on sale at specialty running stores or places like REI or roadrunnnersports.com. Target has Champion brand ones. Just make sure the waistband and liner are comfortable for you.