Douglas Tate asks about bass tutors and how to get in touch with Al and Judy Smith, who do a consierable amount of teaching bass, chord and melody (diatonic, chromatic) harmonicas in a setting of learning to play in a harmonica ensemble (you learn basic theory, reading, time counting, and how to work with others to play a part in a whole). They'll be at the SPAH convention, giving workshops.
I believe they do have an elementary bass tutor (Judy is an accomplished bass harmonicist). They can be contacted at:
Simpson & Smith Seminars 2398 SOUTHERN ROAD RICHFIELD OH 44286-9520
(the US Postal Service likes all caps on addresses)