In an early September, 2014 sequence, Mike Lester did just that in his strip Mike Du Jour. Here's the sequence. (click on images to enlarge)
There were two things I particularly liked about this story arc. First, the cameo was an unusual choice. Most comic strip cameos are familiar figures from Peanuts, Family Circus or other legacy strips. Earl of Brian Crane's Pickles isn't one of those.
Second, I love the way Lester references Crane's strip.
And of course, the primary focus of Lester's humor is about the T-shirt. The grandfather could be anyone and the jokes would have still worked. But making it a recognizable grandfather just added to the fun. At least for some of us.