I haven't been to Philly for a long time. Last time I was there I stayed at the
Thomas Bond House, which was a lovely B&B near the City Tavern (don't go there unless you really have to see 18th century-costumed waitstaff). I looked for the nearby diner that was the inspiration for my pancakes, but alas it seems to have vanished.
Googling for diners did bring me to this one that maybe you should visit:
Little Pete's...