I too am working on a landscape DM's screen (designed to be affixed to the 3.5 landscape screen using paper clips). So far I have ALL the skills, the DC/Damage by level, all conditions, the Object Properties/Material/Composition, the Break/Burst DCs, the attack modifiers, the situations that grant Combat Advantage, the overland travel/terrain times, the equipment and transport tables and the two NPC quirk/mannerisms tables.
Update:
The screen is now at 4 panels, horizontally, and meant to be printed and affixed to one of WotC's 3.5/Modern screens (IIRC, the Eberron screen is also horizontal).
Left panel:
Adventuring gear list, Food and lodging list, Carrying capacity table, DC/Damage by level, Object properties, DC to break objects, Fall severity by level, Overland travel, mounts, vehicles and terrain.
Center-Left panel:
All skill uses.
Center-Right panel:
All actions, with rules and page reference, All conditions, Attack modifiers, Situations that grant Combat advantage and How to determine cover.
Right panel:
Aquatic, Mounted combat, flying, disease, poison and unseen foe rules, Light sources, Languages and NPC Quirks and Mannerisms.
There is still room for a couple of things, so I'm scouring the PHB and MM for what could be added.