I would DEFINITELY suggest Body Glide. We started selling it and would highly recommend it for running in a kilt. I would also suggest a 4 or 5 yard kilt so the pleats and weight doesn't throw you off at all.

While I'm not a runner, I have done a quick jaunt to catch a bus. I would suggest you NOT run with a loaded, heavy sporran. It's like repeatedly punching yourself in the groin. HAHAHAHA... but SERIOUSLY. It was one of those situations where you were in a LOT of pain, but couldn't help laugh at yourself.