Here's another experimental 2.6 kernel. I do know of one bug relating to all 2.6-um kernels: the mconsole proc command (an administrative tool in which I can view files in the Linode's proc directory) tends to cause the UML kernel to panic. This will cause problems for the new IO watchdog I'm planning. I've already reported this to the UML-lists and done a few tests, but nothing's come of either yet.
I don't officially recommend using the 2.6 based kernels yet. If you don't have a need to run 2.6, then don't
-Chris