The ONLY BMW I know of (and I've owned two) where the front & rear brakes were essentially the same was the Farmobil (and it's organ donor, the BMW 700).

Front & rear drum brakes, same size on all four corners. Front wheel cylinders had a bigger diameter than the rear, as you need more braking force on the front axle vs. the rear.

SO, if you want the ultime BMW "real truck", buy a Farmobil - I can still find them.