Carl,
Quite a few people have made pen over the years with "dots," but there has only been one with holes in the dots, or tubes like you have. The one I am referring to was done with cored solder and not tubes.
That is absolutely beautiful! That is not an easy feat for the inexperienced; your experience as a gem cutter SHOWS through!
I have several small tubes of brass, copper and aluminum just waiting to get into a pen. I haven't had the time or been inspired to do it, But this sure is an inspiration.
Beautifully and skillfully done!