Should return info on the machine trust as well. If both the -t and -m switches return ok, then the issue is somewhere in the authentication service.
I have to admit that this is a pretty new problem to me, and I'm a bit more familiar using AD then SAMBA/LDAP setups, but I think you're close.
One of the things I've noticed before is that you can access AD info with wbinfo pretty easily once you have a machine trust. So wbinfo can return good info, but samba will still be broken.
A few things to try, if you haven't already
Check Kerberos auth, Case sensitive and domain must be in caps AFAIK
check to see if the AD server can be reached. If this doesn't work you may want to try a net ads join
to see if the problem is just that the server isn't logged into the AD.
I hope this helps.