Check out the NEW Copic Gasen Fude brush pens.  Featuring real brush filaments/hairs with pigmented waterbased black ink that is both permanent and Copic-proof when dry.  Archival ink with Copic quality makes it one of the best disposable Japanese brush pens around.  Great for oriental calligraphy and sketching, it goes from superfine to bold with one stroke.  $4.79