Hello Nick,
I am currently working on configuring Alfresco Share to work with Kerberos SSO, too.
Unfortunately I have no working configuration for you, but one problem could be the
proper naming in you DNS in the service principal names and the "delegation" option
in you Active Directory for the alferscohttp user.
Could you please post your share-custom-config.xml, krb5.conf, and alfresco-global.properties?
I didn't even get it managed to achieve what you have done, so I would like to see your
configuration.
Kind regards,
Georg