Well the packages built and I was able to install them in my test partition that already has the previously unsupported X.org, so I'm content as far as getting my hands on those packages goes! It seems however that the display manager in amdcccle has seen some changes that invalidate my current configuration.
I used to be able to set both my CRT and TV as "Single display desktop (Multi-desktop)", and set their resolutions independently. Then I'd take the xorg.conf that produces and tweak it everso slightly so the tv actually becomes an X display I can send apps to with "export DISPLAY=:0.1". With the new driver "Single display desktop (Multi-desktop)" might as well be "Disable secondary screen" for all the good it does.
Made real progress towards using the xorg driver today though, so I'll probably only come back to this if that doesn't work out. Thanks again for your help/info Kano.