Here's a really unusual looking pen the Staedtler triplus fineliner. I found this and a purple one at a local stationery store and liked the look and feel. It's a very long, slim, triangular pen with a porous needle point that I thought looked like a 0.5mm width line or larger. The info from Staedtler is that it's about 0.3mm. Hmmm.
Anyway, the ink has a Dry Safe feature: the pen can be left uncapped for days without drying up. I'm sure I'll be testing that out very soon, and hopefully I'll be pleasantly surprised. The ink is water-based, so it will wash out of clothing and there's an airplane safety feature--an automatic pressure equalization prevents the pen from leaking while flying.
Cool looking liquid ink pen, reminds me of the Flair. If you find any, give them a try.