I use a multiseat system at home: one PC, four monitors, four mice, four keyboards, and four soundcards, used by four people simultaneously. It works well, and I like it because it requires less hardware, electricity, and administration effort than four networked PCs. That system is running Fedora 8, for which support will end on Christmas day.
Why not update to Fedora 9 or 10? Because I can't. The (wonderful) changes in X, GDM, and udev made for F9 unfortunately do not support multiseat operation. The new GDM doesn't support multiple seats in the configuration file, ConsoleKit does not support multiple seats yet, X's --noswitchvt flag has broken, and the add-all-input-devices-to-one-X-server device model currently configued for udev and evdev is based on a single user. In contrast, F8 was the best Fedora release ever for multiseat support (though it still required a fair bit of configuration).
I want to continue to use a multiseat system, and I want to continue to use Fedora. I know that there are a lot of other people interested in doing the same, because my Multiseat howto pages (which are getting quite out of date) still receive thousands of hits each month. I also think that making Fedora multiseat-capable shines light on some corner cases (for example, using multiple video cards stresses the video drivers) and addressing bugs there will improve overall desktop reliability.
So I'd like to see really good out of the box multiseat support in Fedora 11. I've proposed it as a Fedora 11 feature and will personally be putting in as much effort as schedule allows to make this a reality.
Want to join me? You can get in touch through the comments, via e-mail (chris at tylers dot info), or on IRC (ctyler).
(Question on the side: I'm trying to collect the hardware to test multiseat across different device configurations. I think the most common video configurations will be two or more Nvidia cards (this is what I use), two or more ATI cards, and possibly on-board Intel plus one or more ATI or Nvidia cards. Does anyone know if Intel makes add-on video cards? I can't seem to find them if they do).
Intel doesn't make add-on video cards, not in the way you expect it.
On the other hand, for older chipsets you have an AGP card called ADD that ads DVI to the intel on-board GPU (and possibly multi-monitor), and the ADD2 that is a PCI-E version of the card.
The two cards only work on motherboards that use an Intel GPU (AGP or PCI-E).