I can think of a few "crossover" recordings where Irish & Scottish musicians play WITH bluegrass musicians in a kind of hybrid style - one is by the Chieftans (The Old Plank Road is the title I think), and the other is under the title "The Transatlanic Sessions", and has been discussed quite a bit here in other threads.

As far as trad Irish or Scottish music as a pre-cursor to bluegrass, that gets harder. Any collection of fiddle tunes by a good Irish or Scottish fiddler should work.