A plug for some old friends of mine: The Adams Duo, a husband-and-wife team playing classical guitar and cello. I first met Jon Adams about ten years ago when we were both playing at the Christopher Parkening masterclass. Here's their website, you can hear clips from their latest album here, and here's the album review from Acoustic Guitar magazine:

The Adams Duo, Montana Skies.

The rich sonorities on this CD by the Adams Duo make one wonder why cello and guitar duos are so rare. Jennifer Adams' lyrical cello work blends superbly with the intricate nylon- and steel-string guitar playing of her husband Jonathan on tunes that range from Jonathan's neo-romantic originals to Celtic and Brazilian tunes to Beatles classics. There are many highlights here, including Jonathan's hypnotic original "December Morning," the traditional "Bridget O'Malley," and an elaborate, imaginative reworking of "Eleanor Rigby." These tunes and the rest of the material on Montana Skies are characterized by great attention to tone and dynamics, played with deep passion and expression.