Illumos has undertaken to remove the last pieces of closed source software (e.g. libc) from OpenSolaris and plans to release a Solaris-compatible fork. They have lined up Nexenta, Berlios, Joyent and others to support the effort to insure the OpenSolaris ecosystem is secure against any attempt to starve OpenSolaris. Of course they hope that Oracle will be a full partner in the effort and benefit, like everyone else, from the open source effort.
Illumos is not a distro in itself, but it hopes to be a starting point or a reference build, for people who do use it to release distros. It plans to be “packaging neutral”, allowing generic packages to be translated to .deb or RPM as desired by each distro. The Illumos releases support x86, amd64, VMWare and VirtualBox. SPARC coming soon.