Hi all I just wanted to pass this on in case noone knew. Mediawiki, the software behind Wikipedia, comes with a little program called 'texvc' that just might be of some use in LyX. This program AFAICT includes a latex math parser and can give useful feedback about syntax errors. It also deals with screen rendering of equations; Apparently it uses 'dvipng' to convert to bitmap form.
If it's not something that's been considered for use in LyX, perhaps it would be worth taking a look at it. http://en.wikipedia.org/wiki/Texvc Cheers JP
