I've carried two pens on my person for a while now, a fountain pen and, as a go-anywhere, do-anything backup, a Fisher Bullet Space Pen.
In recent history alone I misplaced the Space Pen at least twice. That is, until I started to carry it differently.
Being a pen that I didn't use frequently there was no reason to keep it incredibly accessible. So, I thought, why not tuck it away in my wallet. Most bi-fold wallets I've encountered have a perfect place just at the fold. To allow for expansion and the like the wallet is typically designed with a hinge of sorts consisting of a bit more material; the perfect place to stash a small pen.
If a full-sized Bullet Space Pen is still too much, there's always this option, a great way to have the dependability of a pressurized pen without the bulk. Of course, there's always the cap issue; something I'll start thinking about. I will share any brilliant ideas here, of course.
Needless to say, where ever I go I now have a pen. I haven't misplaced it recently, either!
I'm hoping to have a series of "elegant solutions," this, of course, being the first.