i use ubuntu sparc distrubution server !!!
i try with ubuntu-8.04.1-server-sparc.iso
and lucid-server-sparc.iso for ubuntu lts 10.04
you can verify but debian and ubuntu have a sparc 's distrubution
i have an ultra 5 on ubuntu
search to the net at
Ubuntu 8.04.1 LTS (Hardy Heron)
ubuntu is not reserved for i386 or amd64 paltforms
it is ultra linux
regards
philo