Are you talking about the length of the cap, or the total length of the pen. If it's just the cap, then the Vertex RB & FP has a pretty small cap. If it's the total length of the pen, there is a capped small pen from PSI. It hangs from a chain around someones neck. There is another similar version called the pocket pen. Lau Lau Woods sells it. Both the one from PSI & Lau Lau Woods are ballpoints.