Here is a couple pics of what I'm talking about when I see some of the ideas you are hitting around. First pic is your "dice pen", second pic is what I immediately thought of the first time I saw it...
Now, I know what everyone is thinking....oh, cast something in clear PR...blah, blah, blah....but that's been done before Scott, that's nothing new.
Nope! Not where I was going with it. Imagine the dice "pen"....but not as a pen. How about a pen container. Like the round plastic pen tubes, only BIGGER. How about the dice glued up 4 next to each other then stacked 15 high? Bore a hole through the middle just like you would a pen blank, but make the hole a 1" forstner bit! Turn that bad boy round, lop off the top 2" or so, grab a tap/die set and get to threading a cap! BAM! You now have a hand made "dice pen HOLDER"!
See where I'm going with this. I would have never though of this had I not first seen your dice pen.