The Enterprise Volume Management System (EVMS) Project has the goal of providing unparalleled flexibility and extensibility in managing storage. It represents a new approach to logical volume management, as the architecture introduces a plug-in model that allows for easy expansion or customization of various levels of volume management.

Rattle:
This should make its way into the 2.6/3.0 kernel tree. Looks to be far more advanced them the currently LVM (Sistina) that ships with RedHat and other distros.

The comparison of EVMS and other VMs paper is sums up things nicely. And be sure to check out the screenshots.

Linux Enterprise Volume Management System (EVMS)