I still wish for a magic bullet, but haven't been keeping up on this. At some point I resigned to get a different video card and just ignore these issues altogether. From what I've read, my Asus 5770 is a bit more weird than other 5770s, as it's not a direct implementation of the reference card.
Most of the time my setup requires me to have both an DVI-HDMI cable and an HDMI->HDMI cable plugged in, one dangling to nothing and the other plugged into the monitor.
Inexplicably, I just checked the current status of the computer (I know my wife had some issues and moved cables around) and only the HDMI->HDMI cable is plugged in. I'm really surprised by this, i've never gotten 1 cable to work. In previous trials, this only yielded either no video, or "2nd monitor" video over one (or both) cable(s). So, it's very fickle, and I don't consider this resolved. I think it to be one hard reboot away from doing the things it did before.
I'm not sure what personality it's set on (maybe vervet). I know I'm using the odd ATIFrameBuffer hack I mentioned in the post above - I went through a huge matrix of combinations for hours and at best only saw different shades of almost working.
Eh, I didn't help, sorry. Hopefully someone else has a magic bullet we can both use.