In 2005 I was having some issues with big F15k domains. They have a mix of 1gb/s and 100mb/s network cards, which all used the same Solaris driver family. Setting the port speeds meant editing the ce.conf file, and any typos or mistakes here either hung the kernel on boot (not good news in a big F15k domain) or just ignored the settings.
I ended up writing a script that would automatically work out what ce cards were present in the Solaris domain, and then automatically generate a ce.conf configuration file. The script grew in complexity when it became clear the F15ks and mid-frame machines (SF6500 etc.) had a radically different PCI addressing scheme.
I ended up writing and submitting a tech tip to Sun’s BigAdmin website. You can read the whole sordid story at http://www.sun.com/bigadmin/content/submitted/config_ce_cards.html