I saw Scrapple when I was in Reading PA last weekend. Our waitress at the diner said it was pretty popular. She also said people eat either with Maple Syrup or Ketchup. The ladies and I weren't brave enough to try it.
When we go fishing with our friend from Philly he almost always brings some scrapple for a breakfast fry-up. For something that is made of leftover biits ("everything but the squeal") and that is an unappetizing shade of grey to start, it is surprisingly good. I don't think I've seen it in Ottawa, but then I haven't really been looking... :)