Going right back to the original question from the OP:

On my Transatlantic Sessions 3 DVDs, Russ Barenberg gets lead parts in several songs: "Drummers of England" and "St Anne's Reel" to name but two....he plays rhythm, then a lead part for a whole "AABB" cycle then drops back into the rhythm almost withouit you noticing.

I went to his solo gig in a pub in the Peak District about 16 months ago and had a whole evening listening to his lovely flatpicking technique, sitting about 3 feet away from him.