In the last month or so, one of the woodworking websites posted the instructions on making a collage pen with stamps. Would someone remember the site or have a link to it?
PSI sells a kit but I think you must purchase it to get the instructions.
I glue stamps to a painted tube and cast in polyester resin like I make my snake skin blanks. Several threads here on IAP discuss labels and decals. Those techniques can be used also.