Back on topic:
I hear that the Russians have overloaded the 9x19mm cartridge to achieve PDW levels of penetration--probably because they came to their senses and realized that the 9x18mm Makarov cartridge was obsolete from the moment it was designed, and decided to do the "pistol cartridge of the free world" one better. world.guns.ru mentions it here, supposedly for use with their new PP-2000 SMG, though I'm sure they could use it with their own purchased MP5s or Bizon SMGs.
http://world.guns.ru/smg/smg61-e.htm
Such a development strikes me as somewhat redundant, however, since the Russians already have the 9x39mm cartridge for compact and subsonic armour-piercing firearms. They also have lots of old stores of the 7.62x25 Tokarev round which has good armour-piercing potential as well as proven stopping power, and can be used in a handgun platform (which the 9x39mm round is too long to).
I wonder if an "Offensive Handgun Weapon System" could be designed around this new 7N31 version of 9x19mm. I also wonder what could be done with the 10x25mm round, if the 9x19mm round could be turned into a PDW round with enough tinkering.