I've just signed up to techkings hoping to find out whether people use them. Seen some youtube videos of people using pi's as IPTV servers so this lead me to think it must be possible to do a zgemma type setup with one.
I setup one to host a dvb-t (saorview) server for the network in work. The pi used a usb dvb-t stick (hauppage) and I had alot of trouble finding drivers for it. Eventually I got it working and about 10 different "clients" were able to view different channels via their browsers. However because the pi only has a 100meg network card its a bit of a point of slowness in the setup. I ended up setting up a dell mini inspiron (has a bit more oompf and ram) and its now doing the same job as the pi but much faster. I was also able to add a second stick (dvb-c) for analogue cable signals. The dell is using mythtv , the pi I can't recall. There is also a mythtv plugin for kodi, so any kodi boxes on the network get access to the dell's tuners.