In prepraration for an OS installation, I've backed up all the data on cleo with tar. I've placed it on quark in /backup/cleo_sunos5.tar.bz2.
After that, I upgraded cleo to NetBSD 1.6.1 using a standard SPARC install CD. Everything went smoothly aside from some soft errors from the CD drive, which were all corrected. I have put cleo on the standard NIS map from quark, and have it mounting /clients and /usr/exports from quark for the NetBSD package source collection.