I've created a set of tools which quite comfortably allows to scale your game.
If you are interested, go here and check it out. http://www.cbe-software.com/wme-scaler
There are two video tutorials to show you how the tool works so you shouldn't be lost. Please note that this is HIGHLY EXPERIMENTAL tool and so use it only over a backup copy of your game.
Let me know how you like it or if there are any issues you find. Just don't blame me if your project gets destroyed.