Having such little space between the mid plate and heatsink any mods are pretty much non existent. Apart from using a more aggressive fan curve the only real mod you can perform is the thermal pad modification which EVGA has suggested and what majority of other brands use.

Might Help.
  $4.99  Thermal Padding, 1.0mm Thick   SKU: PAD-VD10
 $4.99 Thermal Padding, 0.7mm Thick   SKU: PAD-VD07
 $4.99 Thermal Padding, 0.5mm Thick   SKU: PAD-VD05

NucleusX
From what i can see, the VRM's don't touch the base plate, and left to radiate their heat through the gap into the fins. The obvious
idea is to put a strip of thermal padding across them, but the gap to the heat-sink may be large enough that it would require
quite a thick strip, possibly even thicker than is available, and might have a negative impact on results. There may be enough room
to accommodate a low profile heat sink glued to the top of VRM's, but finding a heat-sink with the right dimensions will be difficult.  

 
I haven't taken apart my 1070 FTW but from other pics I can see the mosfets (which generate the most heat) have a thermal pad on them which is making normal contact with the mid plate. The chokes/inductors have a cutout to allow them to poke through the mid plate as they generally don't generate much heat and don't require active cooling. If you look at your motherboard you'll notice the same thing. The mosfets are underneath the large heatsink surrounding the cpu area and the chokes and capacitors are mostly sitting out in the open.

NucleusX
Where exactly are these thermal pads EVGA are sending out supposed to go ?
Information here doesn't say much. http://www.evga.com/thermalmod/
Do they go right behind and along the VRM's on the back of the PCB ?
 

From my understanding and grasp on things the thermal pad will be going between the mid plate and heatsink, right above where the VRM section is located and more specifically the mosfets.
 
This will allow heat created from the mosfets to be transfered to the mid plate (as it does so now) and then through the new thermal pad into the heatsink itself.
 
As it stands now the heat created by the mosfets is transferred into the mid plate and that's it. It's relying simple airflow from the fans to cool down the mid plate which isn't enough under extreme conditions.
 
Then again no one really knows how many pads we are going to receive and just where they should be going. At the moment we are all pretty much in the dark.
 
All this should be confirmed next week tho when EVGA release the instructions for the thermal pad modification.

A nice little vid for people who wanna see whats under the bonnet.
 
https://www.youtube.com/watch?v=N-brze9p_9E