I had also tested 2 LCD's one from HP and the other one from Viewsonic. The HP also doesn't work because of the small range of vertical frequence. The Viewsonics and the Syncmasters from Samsung (I think) had a wide vertical range (30 kHz - 82 kHz) and are working well with the amiga resolutions.
I decided for the Viewsonic VP191s. Good design and works perfect :-)