Great sources for scans are sometimes in the most mundane places. I happened to park in a further stretch of the parking lot at the grocery store and the little island of dirt nearby had been populated with this flagstone. The distribution was perfect and I knew I'd have to come back to scan it. It was when I was scanning this sample that I realized that I need a T-shirt to explain why I'm taking an obscene number of photos of the dirt. :)
These photoscanned models have 8k maps for reasonable UVs, color, depth & normals. Enjoy!