After many hours of learning and playing with Powerstrip, I have finally gotten a resolution and timing that works well with my TV.
This is obviously a very obscure post, however, I wish it was out there when I was looking for it. If you happen to have a Samsung TXN3245FP with 1080i support enabled, then this may be of interest.
I’ve got my MythTV box hooked up to my TV via the VGA port through a VGA to component transcoder. In order to do that, X11 needs a custom ModeLine to setup the resolution and timing parameters. So, below is the ModeLine that I got to work with my TV. However, these parameters can be device specific, but this should give you a place to start if you’ve got the same TV. Good luck!
# 540p for Samsung TXN3245FP
ModeLine “704×489” 30.587 704 736 808 912 489 518 521 559 +hsync +vsync