I have created an RGB (with sync on green) to VGA converter using a
lm1881. Very easy and cheap circuit. If you have a decent monitor that
will filter out the sync signal leftover on the green channel it should
work great. I also have some VGA to DVI/HDMI scalers which I have used
to convert to HDMI (let me know if you want one), these strip the sync
signal out of the green channel.