Table Tactics used to have available the Central Powers units, which if you combined them with say the infantry figures and artillery from Attack, you could pretty much have what you needed for a WW1 land game, and the naval units, less carriers, would cover the naval aspect. You could pretty much eliminate the Asian aspect as that lasted a very short time. You did have the Emden raiding in the Indian Ocean and Von Spee’s squadron sailing across the Pacific, sinking Cradock’s two cruisers, Good Hope and Monmouth, and then attacking the Falklands, where 4 our of 5 of his cruisers were sunk in December of 1914. Aside from those naval actions, you do not have much at all.
You would need the Mid East and Africa for those campaigns, and Lettow-Vorbeck was still fighting in November of 1918, and you cannot pass up the Arab Revolt and Allenby’s campaigns in the Mid East, nor Gallipoli. The current Europe 1940 board would be about right, reset to 1914. Another option for a start would be the basic Attack Game board covering Europe and the Americas, and then redraw the boundaries.
I am talking to Table Tactics about doing some more WW1 tanks besides the Mark II that they have: the French Renault, maybe a British Whippet as a later war tank, the German A7V, and a Rolls-Royce armoured car for the Mid East. Given the small size of most of your WW1 fighters, you probably would want to use 1/300 scale for the fighters, rather than 1/600. I am checking with another company on Zeppelins, and they already do a nice blimp. Get a mix of 1/2400 scale and 1/4800 scale WW1 ships, and you have the basis for a prototype.
For Countries in the Game, you have the German Empire, the Austro-Hungarian Empire, and the Ottoman Empire on one side, and the British Empire, France, Italy, and a Russian/US player. The US comes in with either the Russian Revolution or the use by Germany of Unrestricted Submarine Warfare. I have thought of a couple of ways to trigger the Russian Revolution, with the option of preventing it if the Ottomans are knocked out soon enough. Hard to say how to handle the Balkans, as Serbia has a claim to be in the game somehow, unless they are controlled by the Russian player until knocked out of the war.
There should be some nice naval actions between the German and UK, and the Italians, the Austrians, the French and the UK in the Med, with some chance for action in the Baltic and the Black Sea. Not sure how to handle the stalemate on the Western Front as yet. However, it is only 2011, so there is time yet.