Two appear to be excellent.

One has burn in, what appears to be the Mac OS X Login screen.

Another one has tiny scratches and arced once, so I probably have to junk that one.

I think what I'll do is take some lesser Graphite iMacs (400 MHz and such) which have good screens and transplant the bottom guts into those, so I still have 700 MHz machines which are a lot more valuable.