I believe this is already capable. Everything I say here is purely speculative, but what I see is that Samsung moved to a 11-pin connector for MHL and the standard 5-pin is no longer functioning. To call it MHL, they probably have to use the same standards for data encoding... but they simply "moved" the pins.
I put "moved" in quotes because of the way in which a standard 4 pin USB cable works (or 5 pin for our case)... you have a +5V, Ground, Data + and Data - (one data to phone, one data from phone, carrying ALL data). Since our phones still sync via 5-pin cables, this means the 5 pins are still "hot" for data like all other phones. I am presuming, that for the 11-pin connector, Samsung simply added a few more data+ and data- connectors (much like having two or three USB ports on a normal computer) but consolidated the ground/5V reference. I could be wrong, but it would make sense.
Lets call the stock 5 pin data connectors (2 wires) USB1. This is where MHL is conventionally sent through and all sycing can be completed through, 5 pin cable or 11 pin cable. If samsung added two additional USB ports to the single connector, lets say MHL is now over USB2 (wires inaccessible to 5 pin connectors). This frees up bandwidth and COM ports on USB1 and USB3 to use for accessories like a USB hard drive and keyboard/mouse. On a 5 pin connector, however, only USB1 is accessible. The Samsung 11pin to 5pin MHL adapter simply moves the data+/- from USB2 to USB1 (standard 5 pin location), so with the adapter you are syncing/exporting video over USB2 on the phone with a standard 5pin cable.
My thinking is such: If you plug in the OEM 11pin MHL adapter, it will also have access to the standard 5pin USB1 connection. Since USB2 is used for MHL, you can then plug any OTG device into the micro USB connector on the MHL adapter to make use of it. The only problem here is power (or lack thereof). By plugging in a USB hub with a discrete power source, plugging this into the MHL adapter, and plugging in the USB device of choice into the HUB, you *SHOULD* be able to get simultaneous data and HDMI. This assumes they put the standard 5 pins to the connector on the side of the MHL adapter and only wired the HDMI to the USB2 area.
Alternatively, you *SHOULD* be able to plug the micro USB cable from the MHL adapter into a computer, and simultaneously be able to sync files while outputting HDMI video. It sort of just comes down to being able to provide power to the MHL adapter on the +5V pin while using the data pins to access the phone. As soon as I have my MHL I'll figure it out, but that could be a bit. If anybody has access to a pinout from a Samsung 11 pin micro USB that would be helpful too.
Again, just dreaming here. I don't know anything about this, but if I was the engineer at Samsung I would choose this over analog outputs like Apple used for their giant connector.
