My first suggestion would be a full restore of the dataabse. If this is not an option, then you are going to be in a bit of a fix. Microsoft will only give "best effort" at fixing any problem. Have you tried backing up the transaction log with truncate_only? Or no_log? After either, you would want to do a full backup immediately.
The DBCC commands shoudlhave a fix option. For most of these, you would need to put the database in single user mode. It looks like you may have already tried these. If these commands did not work, I think your only option may be to restore from the last good backup. Sorry.