Someone on the rage3d forums (mczak) posted a registry hack that actually works! It is dangerous though, as could open up refresh rates not supported by the monitor. I'm sure he won't mind if I repeat it here...
Start regedit, go to HKLM/Software/ATI Technologies/Driver/0001/DAL (or instead of 0001 whatever number your current driver uses).
Insert a new binary value, named "DALRULE_ALLOWNONDDCCRTALLMODESUPTO1600x1200". Set the value to 01 00 00 00.
Or, you could try "DALRULE_CRTSUPPORTSALLMODES" and set this to 01 00 00 00 instead. (Both work here perfectly, the difference being that one allows resolutions up to 1600x1200x200, the other 2048x1536x200.
That's it, just reboot.
IMPORTANT: you need to set the refresh rate for all resolutions you want to use manually with regedit, since the driver will likely set them to 200hz when you switch resolutions, so you won't get a picture unless your monitor can handle that. So, go to [HKLM\System\CurrentControlSet\Services\Class\Display\0000 (or whatever number your monitor has)\MODES\x\y,z]. Make a new string "RefreshRate" and set it to "85" or whatever you like and your monitor can handle.
If you forget to do this you might be forced to boot in safe mode since you might get an "out of range" value by your monitor upon boot-up...
I found that the last step (after the 'IMPORTANT') was not necessary, presumably because I'd used 'HZTool' to set up refresh rates beforehand. This was the ONLY fix that worked for me, other than having 'Powerstrip' run on startup.
And if mczak reads this - thanks! I would have posted on rage3d, but my account seems locked out.