From MARKERTEK.com  - $39

LANC Camcorder Remote Control Controls/Functions: Connecting Plug- Plugs into the LANC terminal of a compatible camcorder/camera to permit ... Our Part# LANC-1 Our Price $38.99

http://www.studio1productions.com/zoom-controller-menu.htm

http://www.signvideo.com/zoom-commander-digital-zoom-controller_II_pro.htm

dvc30 - $179 - http://www.signvideo.com/zoom-controller-lanc-dvx-menu.htm

Zoom Commander - http://www.signvideo.com/zoom-commander-digital-zoom-controller_II_pro.htm
  for dvc30, 80 - http://www.signvideo.com/zoom-commander-zoom-controller-dvx-for-dvx100-dvx80.htm

VariZoom - $199 and up -  http://www.varizoom.com/controlsindex.html