This article implies there is... I just can't seem to find the details:
Nexus One Getting Update to Android 2.2.2
Unfortunately, the same time Froyo 2.2.2 came out, so did Gingerbread, so every ROM developer of which I'm familiar stopped working on Froyo and started on Gingerbread. CyanogenMod6 is also based on the 2.2.1 kernel.