A year or two ago I bought a combined DVD and VHS player. It is a Samsung DVD V540.
After all this time I only recently tried to see if it could be multi region compatible. And it can be!!!
The instructions for unlocking the Samsung DVD V540 to make it multi region. (assumes purchase in Australia.)
Empty DVD player
Turn power off at power point
Turn power on
Wait until no disc displays
Press Subtitle
Enter 7, 6, 8, 8, 4 on the remote
The current region (4) should display on the screen in the top left
Press 9 for multi region
Press Subtitle
Press open on the main unit
Press close on the main unit
Turn power off at the power point
DONE!!! Your DVD player should now be multi region capable.