Dusan Bogdanovic, guitar
Dusan Bogdanovic is one of the most interesting "classical" style improvisers. I'm tempted to pick up a guitar and go through the parts of his Counterpoint For Guitar (and if only there were an affordable edition of it) that deal with improvisation, if only I were young enough. He has gone a lot farther than most of the keyboard improvisers who seem to be more hampered by vertical sororities that stifle their melodic lines. Apart from some of the great French improvisers who seem to have been freed by such things as polytonality. But that's a generalization.