What i am waiting or trying to develop are: 1. Possibility to have backup-MX that does all the filtering what primary-MX do, but act only as backup-MX 2. PostgreSQL, in external or internal, i don't care, but soon i have to get something to work. Of course i can just install one, but i want to manage it through ISPConfig. 3. Ability to easily move sites/clients/databases/emails from one host to other in multiserver setup. If you have opinion, please say it at loud. If i could code php even half as i do with bash, someday something could came ready...
Why would you make your setup on the backup MX side more difficult? Once your primary MX is back online, it will filter everything for you... On the backup MX you can allow the whole domain. See: http://www.howtoforge.com/forums/showthread.php?t=49546
Because we already have every mail-address in mysql, there is no reason to build internal backscatter-server. If i do it like in link you send, and for some odd reason primary-mx fails for day or two, it will collect thousands of unwanted mails. For performance-wise it does not matter for us, but it is just not the way i'd like to do it.
