The Dream Pinball program file (dp3d.exe) can be modified to support higher resolutions and widescreen displays. To do so, you will need a hex editor (if you don't have one installed, I would suggest the free HxD). These changes will replace the 1600x1200 resolution setting in-game (normally the highest option available) so please ensure you have selected this option first.

1). Work out the hexadecimal equivalents for the resolution height and width you wish to use (Windows' own Calculator in Scientific Mode can help here), e.g. 2560x1600 would mean a width of a00 and a height of 640, 1920x1200 would be 780 by 4b0;

2). Make a backup copy of dp3d.exe (HxD will create a .bak file backup by default, but it is always best to be sure on this) - I would suggest renaming it something like dp3d.exe-orig;

2). Use your hex-editor to open dp3d.exe;

3). Navigate to offset 00039e84 and put the width value in reverse order (so for 2560x1600 you would change the values to 00 0a);

4). Navigate to offset 00039e8e and put the height value in reverse order (so for 2560x1600 you would change the values to 40 06);

5). Save the modified dp3d.exe, close the hex-editor and run the game - the initial splash and menu screens won't change but once a table is started, your new settings should take effect. Enjoy!

Credit to the Widescreen Gaming Forum which had a thread on Dream Pinball 3D, but the offsets there were for a different version, and won't work with the GOG release.