4.5mm rod beadable pens

i am looking for a pen that will accept 4.5mm beads in it's center that can be changed in and out.  i have tried to attatch a picture, but am not sure that it is being added.  if able to make these, please let me know your minimum and price.  i do not need the beads i already have them, but am looking for a manufacturer of this style of pen.  i would like to purchase a small amount to begin with, to check the quality.

please email pictures/prices/minimum to   (deleting the spaces between the letters), or if you think you will be able to make these, please email me for the picture if it doesn't come through.