On #illumos the UFS file system isn't long for this world. It won't survive Y2038, for starters.
But you can still install the latest #Tribblix to UFS root, on a UEFI system no less. It's a bit tricky, and has some complex manual steps to get there. I'm not sure if making it easier is a good idea, as UFS isn't really something we want to encourage.
jack@tribblix:~$ df -h /
Filesystem Size Used Avail Use% Mounted on
/dev/dsk/c1t0d0s0 7.4G 664M 6.7G 9% /