Isn't there a way to do *almost* the same thing in GUI?
like instead of using handicaps etc, you use Chat.
Easier to implement
Players can choose an appropriate handicap
No upper limit to races
Made entirely in GUI
Works in standard WE
Players start a few seconds late
This was used in the Blizz map 'Monolith' if it helps.
Of couse, you need to turn it off (prevents players from doing so when they are defeated, giving them a free revival)