Hi scuba. Sorry to hear about ur illness. Hope it's something you can recover from. You've been a great help, so if you would like to lend a hand in the future it would be greatly appreciated. Hope you get well soon.
As run088, says the signal is going to be different on all tv's. I've got a tv and a monitor that work fine with 720p and no overscan issues. Personally I use 640x480, because as run088 says again I could only watch many flash videos in a small window in 720p, as the processor was overloading (and that's with a ram upgrade)
But anyway I've made a kind of giu frontend for fbset. It does simple things like expand or reduce the screen size and move the screen up, down left and right. It will do it in a new display, so if your tv does not like the setting you select and can't see anythin then it will return to the old display in 15 secs. I've only tested it on my monitor at 640x480 so far, but it should work at other resolutions.
any way, you can find it here:Screen_resizer