Sorry I typed that from memory the ugly principal I mentioned was:
 
Default principal: colin\@CSL.CO.UK

Hi Colin,

The support for enterprise principal is coming in sssd-1.10 which is part of Fedora 19. In the current version that is included in Fedora 19 there is a couple of bugs related to the enterprise principal support, so I would recommend waiting for the next release (hopefully Monday).

Upstream ticket:
https://fedorahosted.org/sssd/ticket/1842

Is my issue addressed by the enterprise principal implementation? 
And will it generate these slightly odd looking default principals?

(In reply to Colin Simpson from comment #4)
> Is my issue addressed by the enterprise principal implementation? 

Since you can kinit with the -E option then I think it would.

> And will it generate these slightly odd looking default principals?

We enable canonicalization by default then the principal should not look ugly :)

Can you try:
kinit -E -C colin.UK

do you still get an ugly principal?

Yes that has cleaned up my principal. It now just says just colin

Will this make it to F18 or will 1.10 be F19 purely?

(In reply to Colin Simpson from comment #6)
> Yes that has cleaned up my principal. It now just says just colin
> 
> Will this make it to F18 or will 1.10 be F19 purely?

Currently we are planning F19 only because there is a huge number of changes in 1.10 including different packaging. If 1.10 will ever be present in F-18 then it's going to be later when we are sure there are no regressions.

However, we could start with a private repo on repos.fedorapeople.org. Also, we already have a repository with nightly builds - http://jdennis.fedorapeople.org/ipa-devel/ But please note these are really nightly builds, so breakage happens from time to time. I would only recommend this repository for testing or development.

sssd-1.10.0-8.fc19.beta2 has been submitted as an update for Fedora 19.
https://admin.fedoraproject.org/updates/sssd-1.10.0-8.fc19.beta2

Package sssd-1.10.0-8.fc19.beta2:
* should fix your issue,
* was pushed to the Fedora 19 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing sssd-1.10.0-8.fc19.beta2'
as soon as you are able to.
Please go to the following url:
https://admin.fedoraproject.org/updates/FEDORA-2013-10683/sssd-1.10.0-8.fc19.beta2
then log in and leave karma (feedback).

Package sssd-1.10.0-10.fc19.beta2:
* should fix your issue,
* was pushed to the Fedora 19 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing sssd-1.10.0-10.fc19.beta2'
as soon as you are able to.
Please go to the following url:
https://admin.fedoraproject.org/updates/FEDORA-2013-10683/sssd-1.10.0-10.fc19.beta2
then log in and leave karma (feedback).

Just FYI, as you correctly identified this issue is resolved for me in F19.

(In reply to Colin Simpson from comment #11)
> Just FYI, as you correctly identified this issue is resolved for me in F19.

Great, thank you for testing!

One thing I think I have found is that offline password caching doesn't seem to be working for me. Maybe I'm doing something wrong but the debug looks a bit like it's looking for the UPN name in created DIR cache.

This is F19 sssd-1.10.0-16

Debug:

Mon Jul 15 21:03:56 2013) [[sssd[krb5_child[23084]]]] [need_switch_to_principal] (0x0200): Comparing default principal [colin\@CSL.CO.UK.TLD] and new principal [colin\@CSL.CO.UK.TLD].
(Mon Jul 15 21:03:56 2013) [[sssd[krb5_child[23084]]]] [map_krb5_error] (0x0020): 1283: [0][Success]
(Mon Jul 15 21:03:56 2013) [[sssd[krb5_child[23084]]]] [pack_response_packet] (0x2000): response packet size: [49]
(Mon Jul 15 21:03:56 2013) [[sssd[krb5_child[23084]]]] [k5c_send_data] (0x4000): Response sent.
(Mon Jul 15 21:03:56 2013) [[sssd[krb5_child[23084]]]] [main] (0x0400): krb5_child completed successfully
(Mon Jul 15 21:03:56 2013) [sssd[be[iongeo.com]]] [child_sig_handler] (0x1000): Waiting for child [23084].
(Mon Jul 15 21:03:56 2013) [sssd[be[iongeo.com]]] [child_sig_handler] (0x0100): child [23084] finished successfully.
(Mon Jul 15 21:03:56 2013) [sssd[be[iongeo.com]]] [sss_child_handler] (0x2000): waitpid failed [10]: No child processes
(Mon Jul 15 21:03:56 2013) [sssd[be[iongeo.com]]] [read_pipe_handler] (0x0400): EOF received, client finished
(Mon Jul 15 21:03:56 2013) [sssd[be[iongeo.com]]] [parse_krb5_child_response] (0x1000): child response [0][3][37].
(Mon Jul 15 21:03:56 2013) [sssd[be[iongeo.com]]] [cc_dir_cache_for_princ] (0x0400): No principal for colin.UK in DIR:/run/user/4000/krb5cc
(Mon Jul 15 21:03:56 2013) [sssd[be[iongeo.com]]] [krb5_auth_done] (0x0020): No ccache for colin.UK in DIR:/run/user/4000/krb5cc?
(Mon Jul 15 21:03:56 2013) [sssd[be[iongeo.com]]] [check_wait_queue] (0x1000): Wait queue for user [colin] is empty.
(Mon Jul 15 21:03:56 2013) [sssd[be[iongeo.com]]] [be_pam_handler_callback] (0x0100): Backend returned: (0, 4, <NULL>) [Success]
(Mon Jul 15 21:03:56 2013) [sssd[be[iongeo.com]]] [be_pam_handler_callback] (0x0100): Sending result [4][iongeo.com]
(Mon Jul 15 21:03:56 2013) [sssd[be[iongeo.com]]] [be_pam_handler_callback] (0x0100): Sent result [4][iongeo.com]
(Mon Jul 15 21:03:56 2013) [sssd[pam]] [sbus_remove_timeout] (0x4000): 0x7fce229194f0
(Mon Jul 15 21:03:56 2013) [sssd[pam]] [sbus_dispatch] (0x4000): dbus conn: 7FCE2290E410
(Mon Jul 15 21:03:56 2013) [sssd[pam]] [sbus_dispatch] (0x4000): Dispatching.
(Mon Jul 15 21:03:56 2013) [sssd[pam]] [pam_dp_process_reply] (0x0100): received: [4][iongeo.com]
(Mon Jul 15 21:03:56 2013) [sssd[pam]] [pam_reply] (0x0200): pam_reply called with result [4].
(Mon Jul 15 21:03:56 2013) [sssd[pam]] [pam_reply] (0x0100): blen: 77

Can you also paste the contents of /var/log/sssd/krb5_child.log during the offline attempt?

This bug was fixed a long time ago, closing.