Why 5:4? The Amiga was designed to be viewed with a 4:3 monitor, so you'll only get oval circles if you use a 5:4 panel..
This one might be as good as it gets, and I have to say I am tempted. My current LG is 5:4 and I don't like that.
Of course the ultimate "goodness" of that depends on how well the adjustments work.. Some LCD monitors have a hard time getting all of the Amiga signal.