Nost: Actually the Germans did. The Germans being the other excellent weapons and hardware manufacturer (H&K, Steyr, Walther, etc). During WWII, they did quite a bit of research and actually developed a variant of the MP40 for this purpose.

I got to field test the Galil SAR. Excellent weapon, all the way around. I especially like the integrated bipod and oversized charging handle (which you can use from either side of the weapon, and with either hand). Built like a brick s**thouse, with a much better gas system than the AK, AKM or AKS models. The Finnish Valmet is another really nice AK variant.