http://kerneltrap.org/Linux/Who_Uses..._Stable_Kernel
the example I know personaly very well is DSL Linux which refuses to use kernel 2.6 because the image is a bit bigger.
OpenBSD? Please?
Would be nice if you test FreeBSD + UFS and FreeBSD + ZFS..
I am looking forward to the comparisons and appreciate whatever you are able to put together. It was some of the earlier comparisons that brought me here in the first place, so keep 'em up!