Since OS X sort of qualifies as *NIX here goes...
When upgrading an Intel Mac from 10.4 to 10.6 I was able to skip 10.5 by using the $40 (after tax) upgrade package instead of the $200 complete package Apple wants 10.4 users to buy. It's been running for three or four days now with no serious problems. I just had to manually download newer versions of a couple of third party programs.
They've finally implemented something like the pager. They call it Open Spaces. By default it gives the user four virtual screens.
Later Mike