Before I get your hopes up, I'd better rephrase that.
Although they're best known for their theme-y baby towel sets and costumes, Mullins Square also makes diaper covers called My First Boxer Shorts that look like--you guessed it--boxer shorts. They're for sale at MyMamaBear.com, where they're only marketed for boys ["Adorable first boxer shorts for your little man! Now he's just like Daddy!"} whose dads don't go commando or wear tighty whities.
Still, I'm sure if those boys are ready to take that big step in their relationships, their little girlfriends can borrow them.
As for my first boxers, I eBay'ed them all years ago [hey, b-school doesn't pay for itself, you know.]
My First Boxers are available in a bunch of silly patterns, plus camo. They're $15. [mymamabear.com via babygadget]
Its a shame, all this sexist marketing and stuff. I'm typing this in a pair of boxers while my husband lounges in his tidy whiteys. [it's hotter than heck in DC - I came home from work to find all members of my family topless and in their underwear in front of the fan] I'm so getting a pair of the hawaiian ones for my daughter. We already buy half her clothes from the boys side (the only place to find bottoms that aren't embroidered up the wazoo with bunnies or hearts or butterflies), so why not these?