I wish I had a good suggestion for you.

One thing to watch out for is the inability of the TV to report its resolution
to the computer with most VGA to HDMI adapters. That means you'll have to force
Ubuntu to produce the proper resolution. I have no personal experience with it,
but I've read messages from people who were tearing their hair out.

If memory serves, this was also discussed on an episode of Tekzilla.