I have a Zenith (LG) DVD player with upscale conversion that plays DVD's at 1080i.
The player is about 1 1 /2 years old and was one of the first with this upscale technology. I do have a hack that I found a link on a forum that will make it region free. I have the file on my computer but never installed it or intend to install it since I've never had the need to play region free disks.

Below are the instructions how how to install this particular hack, I would believe others are simialar. I would have never thought about the burning in iso mode.
I doubt that this hack would permit it to play PAL DVD's, however, both the DVD player and TV can be adjusted for different video modes.
Everything works fine, and if it ain't broke, don't fix it.

1) Unzip the folders and files to the hard drive in exactly the same order.
2) Burn the folder "RMT000" (including sub files and/or folders) to a blank CDR
3) Make sure you set; 'close' disc and session
4) Make sure you burn the disc in ISO mode (not joliet)

Insert the disc in the player and follow the screen instructions