But my surprise purchase was actually these mechanical pencils (I am a sucker for stationary).
There's a pretty good range of designs. Unfortunately they do have a bit of a plastic feel to them :(
My camera refuses to focus on something as tiny as a lead nib so here's a photo of the ones I ended up getting:
They're designed so that it keeps the tip sharp as you write (a bit of problem if you're familiar with mechanical pencils) by rotating the lead a little bit every time you press down to write. There's a cool video here: http://www.mpuni.co.jp/product/movie/kinou_kurutoga/index.html#a01