Russ Barenberg is definetly one of the cleanest sounding acoustic guitar players around. If you want to help mke your playing smoother, one of the best things to use for developing fluency is to learn a number of old bluegrass tunes. Although playing scales is useful, learning to play some of the old Irish and Bluegrass tunes is definitely a way to practice, up your technique a little and at the same time it will help you develop an ear for melody as well. Jerry Douglas is by far my most favourite Dobro player.
I will continue to post youtube videos of great acoustic guitar players. I also have some tremendous ones at www.the-guitarplayer.com
Enjoy the Russbarenburg and Jerry Douglas youTube video