I have been looking but neither Gparted nor KDE Partition Manager can handle LVM. Working with the command line is probably fine but it would be clearer to have a GUI tool here. Does such thing exist?
Partition manager that can handle LVM?
partition;lvm
In RedHat's set of administration tools, there's system-config-lvm, which is optionally installable in other distributions like Fedora and Debian.Recent versions of gnome-disk-utility support LVM.The newly-released KDE 4.6 gains udisks as a Solid backend, which should provide LVM support.  (Out of the three, this is the only one I haven't tried.)