Incidentally, apart from the fact that the graphics conversion (for the screen) blocks the execution of LyX, I think that LyX 1.3.x/Win should now be a fully-functioning equivalent of LyX/*nix.
The child process fixes have not been committed to LyX 1.3.6cvs yet. I still have to apply a subset of your "win32_10jan05.diff" patch
If you really are using it in anger, then I'm sure that you'll discover bugs. Please report 'em all.
I will do so, promised!
Michael