I am no professional photographer, but I do get asked to give presentations based on my style of presentation. You did right telling them no. I've turned down a few presentations because my knowledge of the subject matter was not as good as it could be. On the other hand I think you might be cutting some potential business opportunities. Maybe this could be the start of a new avenue.
Could you transmit the same emotion with color film? Have you tried to do it seriously, not just snap shots?