From the link provided Sun has provided the grub project the changes required to allow grub to boot solaris/opensolaris now that they use grub. It would be nice if the grub shipped with fedora could incorporate these changes.
the link referred to is here: http://www.sun.com/bigadmin/features/articles/grub_boot_solaris.html Peter is this still under consideration?
With the cancelling of opensolaris seems it isn't needed anymore.
http://illumos.org/