Well, two steps forward, one step back. I purged fglrx* and it wiped xvba-va-driver, which I gather is well and good. Installing the kernel ChrisXY suggested went smoothly:
3.13.0-031300rc3-generic #201312061335 SMP Fri Dec 6 18:37:23 UTC 2013 x86_64 x86_64 x86_64
Adding the oibaf went well. I did an 'apt-get dist-upgrade' and it added what I gather is the llvm 3.4 snapshot & upgraded a bunch of others.
That seemed to upgrade mesa as well: Candidate: 10.1~git1312101143.1e7149~gd~s
The following NEW packages will be installed:
The following packages will be upgraded:
libdrm-intel1 libdrm-intel1:i386 libdrm-nouveau2 libdrm-nouveau2:i386 libdrm-radeon1 libdrm-radeon1:i386 libdrm2 libdrm2:i386 libegl1-mesa
libegl1-mesa-drivers libgbm1 libgl1-mesa-dri libgl1-mesa-dri:i386 libgl1-mesa-glx libgl1-mesa-glx:i386 libglapi-mesa libglapi-mesa:i386
libgles2-mesa libopenvg1-mesa libwayland-client0 libwayland-cursor0 libwayland-server0 libxatracker1 xserver-common xserver-xephyr
xserver-xorg-core xserver-xorg-video-ati xserver-xorg-video-intel xserver-xorg-video-nouveau xserver-xorg-video-radeon
After checking that xorg.conf was renamed I rebooted to Debian, updated grub and came back to Kubuntu. Lo and behold both monitors showed up both in lightdm and in KDE. I was able to use systemsettings and arandr to set up the monitors the way I wanted (side by side, one rotated), resolution was good. Direct rendering is working, as are desktop effects. fusion-icon segfaults, but that is no big deal, though I was hoping the extra punch I got from the upgraded video hardware would enable me to routinely use a bit more eye-candy without a performance hit. And I can now move my cursor all the way to the edge of my right monitor, instead of having a 20mm no-go zone like I did with the repository fglrx driver!
However there is some bad stuff, as well. Though the windows are much more responsive then they were under the stock radeon and fglrx they are still not as responsive as they were with radeon on Debian testing with the 6 year old onboard graphics. Minimizing takes a perceptable moment, restoring my firefox window from the taskbar takes a full second or more. I can live with that. But video playback has all kinds of weird artifacts, particularly certain types of HD content, weird shadowing, messed up colors, strange little frames, etc. At least video playback worked well under fglrx and the stock radeon. Here is a screenshot of a PBS crafts program from my hdhomerun TV box:
I gather following Melcar's suggestion will get me to the same place, since it just uses a slightly different kernel, but what the heck, I'm downloading the packages from http://kernel.ubuntu.com/~kernel-ppa...e/v3.12-saucy/ and will give it a spin, as well. Maybe the 3.13 kernel has regressions. If that still gives me green skin-tone I'll try mmstick's suggestions, probably the fglrx from AMD first, and then the script (because I've already added a bunch of stuff to the open source stack I guess I should purge all the new non-repo programs from oibaf first. But I've messed with it enough for today, I'll play with again tomorrow, time to wok my dog, etc. Thank you guys very much for the suggestions, I feel like I'm making progress.