Back in the day, I created a font called "Scribble Flinger" that would put smudges and stains throughout if you enabled the contextual alternates. I came up with several alternates for each glyph, and was pretty pleased with the result.

It's a free font, and I occasionally see it used in posters for rock shows or other "alternate" events.

But your point is right on. I only created three alternates per glyph, if I remember correctly, so if you were to try to use it for an entire page of text, it would reveal its tricks pretty quickly. For just a title or header, I think it holds up.