There are 2 sight bonus skills (one much more effective than the other) as well as frequent sight bonuses on equipment. Half way through the game (with a couple points in Elven Sight) I had to start avoiding equipment with sight bonuses, so my sight range wouldn't get too much larger than the screen size (that way the fog of war can be used to keep track of where you have explored already).
You could just use
DAD's item editor to give something a large sight bonus. In a test, a ring with a +1000 sight bonus cleared much of the fog of war in the wastelands (trying to equip a second +1000 sight ring crashed the game). For playing, a value closer to the screen size would likely be safer (IIRC a sight range of 18 should clear the majority of the screen playing at 1024x768, while the stating value is 12).
The base sight value can also be edited (see
Some more hex offsets... and
Teleporting Anywhere, via hex editor).
