Here is a basic scenario for this mod. This mod still needs some work, as tech costs need to be balanced and you need a new gamefont, but overall it's pretty good.
Was giving this a go last night - playing as Britain. Think the science levels need to be tweaked somewhat as each research project was being churned out in a turn.
By the time you've traded with allies the whole tech tree is researched before the end of 1914
Britain also starts with way too big an army, and too small a navy (should be a load of Dreadnoughts and even a couple of Super Dreadnoughts). With the bulk of the fleet starting in the North of the British Isles (Scapa Flo)
All that said I enjoyed it, and after some initial successes I found my advance into Imperial Germany quickly got ground down.
I think the thing this perhaps highlights is that it is difficult to push the nations along the historical path.
As such I'm thinking I'd like to try to build a map that concentrates solely on the Western Front. Perhaps 2 versions - one for the Schlieffen Plan, and the second from December 1914 when it had moved into trench warfare, both with just Britain, France, Belgium and Germany in play.
If events could then be added to represent;
British Colonial troops (random event, that adds a single infantry unit at a time)
1915/16 British troop numbers boosted significantly by 'volunteer' army
German troops from the Eastern Front in 1917
A small smattering of US troops in 1917
A large number of US troops in 1918