Smoth made a suggestion (which at first I didn't take seriously) yesterday, but the more I thought about it the more it intrigued me, so here is the idea.
Instead of having typical rts game starts. When the game starts, give the player 30 seconds (or so), in which time no orders given to units can be carried out (IE, the game would act as though it were paused).
During this time, the player gets 220 metal to spend on anything he wants within the green start boxes area.
So, if he wanted he could spend it on a powerplant and 2 mexes, or on 5 mexes, a factory and 3 powerplants (considered universally to be the "normal" starting build order), or any other combination.
After the 30 seconds were up, the game would actually start.
In thinking about it, I feel as though this could really make the game start dynamic (as well as get rid of the boring first minute of buildup and get right to the fun stuff.
Feel free to tack on suggestions to this. It's just an idea, but one that I think might have a lot of merit.