I can't believe you found some bamboo that tight, knuckle-wise. Nice job on the whole thing (fit and finish just isn't my lingo yet). I've been talking to my wife about turning some bamboo, but the knuckles, or webs, whatever, were too far apart. I'd probably chop it up anyway. I wonder if you can dye it, so the joints stand out. Not that this pen needs anything more.
Is that a cigar pen kit. It looks like the ones I just bought from woodturningz. Nice.