[M4tt0]

Gee, I forgot after reading all that stuff, testing (and increasingly being disappointed). OK, another chance, another atttempt:

(1) Modeline from the MythTV database (Sony KDL-40S2000): "1360x768" 85.500 1360 1432 1544 1792 768 771 777 795

(2) After figuring out that the xorg.conf ceased to exist, I created the following file (10-monitor.conf) in /usr/share/X11/xorg.conf.d (device identifier taken from lspci):
http://paste.ubuntu.com/8367042/

(3) After rebooting, the Xorg.0.log file seems(!) to indicate that the modeline is read correctly (line 218) and enabled (line 243) of...
http://paste.ubuntu.com/8367050/

(4) Unfortunately the screen remains black though... :-(

Any idea what I should modify / what else I could try?

Thanks again, fritsch!