The DeforaOS desktop aims to work across all form factors from mobile devices to desktops and "focused on usability, coherence and integration, and therefore featuring a number of desktop applications." DeforaOS is a multi-purpose, kernel-independent operating system that's been an ongoing work-in-progress for several years. Their desktop environment should work though on almost any GTK2-supportive OS.
Defora requires at least GTK+ 2.6 but also has compatibility with GTK+3. The Defora project does have packages for Debian, FreeBSD, and other operating systems.
If you're interested in more details on the operating system or its desktop environment, check out the project site and the PDF slides that were presented last weekend at FOSDEM.