AudioWarrior's virtual banjo features strummable chords and pickable notes 22/03/10
Here's what AudioWarrior have to say...
The Audiowarrior Mountain Banjo Reason Refill
is a special sounding Open G tuned virtual banjo that will add true STEREO-SAMPLED banjo character, spirit, and musicality to your songwriting compositions.
...Includes a Chromatic Combinator for standard note mapping and use of Banjo MIDI files plus STRUMMABLE NNXT Combinator Chords & STRUMMABLE and PICKABLE NNXT Chords with root notes that default to C3 ascending. NN-XT Advanced Sampler Banjo Chords