Sure, in "Pearls Before Swine" the characters are not only aware that they are comic strip characters, they can bully their artist and kidnap characters from other strips. "Mother Goose and Grimm" chooses to take a more Star Trek-y type approach. Now I'm just waiting for Grimm to stumble through a rip in reality caused by a boiler explosion and land in "Blondie." Except, wait--in the Blondie universe, all comic strips exist in one giant shared reality (witness the character party that Blondie and Dagwood had for their 75th).
Except, wait again: There's Grimm, right in the front row of the 75th anniversary party. The two strips already occupy the same reality . . . hmm. Maybe I'm getting a little too hung up on continuity. Maybe.