I'm one of those nuts that actually has a knife in the Altoids-size tin.
Not that I don't carry another as well whenever possible (right now I'm working in a "secured" building where it's not). As a matter of fact, in a mall knife store recently, a young lady showing me a knife asked if I carried one. I thought I had three on my person (including the one in the PSK). An actual inventory turned up five, two I had forgotten about...
For years the one that rode in my Altoids-size (Windmill lighter) tin was the "orignal" size Gerber LST, which just fits the long way without having to go diagonal (the Gerber LST Ultralight is much smaller still, but barely usable).
That's now been replaced- the Fallkniven U2 is, IMHO, a much better knife, and is virtually the same size.. even a hair shorter, and a bit lighter. Certainly more solid, and the steel is impressive.
Of course, it costs quite a bit more ($65 street vs $15 street), but I've never been able to budget knives or books...
So far, it's an impressive little blade. Those looking for a tiny, lightweight, last-ditch backup knife, one for a small kit, or an ultralight-minimalist knife for when you're counting every ounce, might want to consider it.