I'm not sure about a good single edged fixed blade of that length, but if you are interested in a folder I bought one of these a little while back:
And it is now my EDC knife. A Spyderco Delica with the wave feature. The wave (with a little practice) opens the knife as it is pulled from your pocket. It has a 3 inch blade, and is a back lock instead of a liner lock. I bought it from the store I linked to, they were very good to work with too, so look aroudn the sight some, they seem to have good deals.