War es wirklich?

It should solve the following problems:

• easy setup
• make the different machines in the home network aware of each other, and play together well
• communication server setup
  • imaps accounts, accessible from inside the home network and from the outside (using a Fritzbox with dyndns, for example)
  • it should fetch email from different external accounts
  • spam filtering on the server side
  • general filtering on the server side
  • virus checking on the server side
  • easy to configure
  • Kolab-based?
• out-of-the-box email encryption
• syncing of calendar, addressbook, email data with mobile devices, also remotely (ssh tunnel?)
• file server with shared dirs and user dirs, and access control
• fulltext indexing/search of files on the file and mail server and the client installs
  • per user, matching the access controls
  • handling of encrypted email (how? And that would require to encrypt the respective index, too, or this would be a leak.)
• print server
• media center setup, NX-enabled, LinuxMCE/KDE-based?
• workstation setup, NX-enabled, KDE desktop
• setup for notebooks including the ultra-low-end (eeePC, etc.), KDE desktop
• setup that runs off USB drives, KDE desktop, automatic hardware and network detection, configured for easy access to emails, files, etc. at home when outside the home network
• encryption support for all user data, whole disk encryption for notebooks and USB drive installs; in general: secure setup of these mobile installs for operation in a "hostile" environment (when outside the home network)
• NX access to the home machines from outside the home network through ssh tunnels and port forwarding by the router
• graceful handling of parts of the network being switched off at times
• easy backup of all systems, e.g. to a USB hard drive attached to one of the machines
• easy updates of all systems, local cache of package repository

Many of these things are possible today if one likes to tweak and script things. A few things on this list I've tried myself.

This looks more like a packaging/distro-creation task than a coding one to me.
Well, probably some of both.

Is there any distro (or customized spinoff) that focuses on making these things easy by making sane assumptions and by introducing sane conventions, if necessary at the expense of some flexibility?

The Open Document Format is the file format for electronic office documents. It is standardized as ISO/IEC 26300. Implementors include OpenOffice.org and KOffice.

Some resources:

Das deutsche Kubuntu-Forum hat eine kleine Anleitung, wie man KDE 4 Beta1 in Xephyr laufen lassen kann.

I just learnt that Jos van den Oever has been applying the fuzzing tool zuuf to his software Strigi(*). This is excellent news as a full text indexer has to process lots of different types of files, and some of them may come from unknown/untrusted origins, for example email attachments. Spending some extra effort into making indexing rock-solid will hopefully help avoid exploits via the indexing daemon.