How about finishing game in 15 turns ?
*Super Heavies are disabled : TA, JT, SP and Maus (if they move it back)
1st-5th turn - max t3; light artillery (+ nebel) and medium tanks unlocked, uncommon units unlocked.
6th-10th turn - t4 unlocked, Rocket and Heavy arty unlocked, rare units unlocked, Heavy tanks unlocked (Except KT, Churchill Croc and other Super Heavies).
11th - 15th turn - Churchill Croc and King Tiger unlocked. Bonus warmap points.
It is just an example, but tech restriciton would be nice