Tradsteve, you need to be more specific about what you mean by banjo and style. As an example, I play tenor (one of the 4 string varieties) and use the most common "Irish tuning" GDAE. The tenor is also used in Jazz but normally in CGDA tuning.

I would guess that you are thinking of a 5 string - don't know musch about them but there is frailing, clawhammer, melodic... for starters....

Jon