I have a rooted Nexus 7 with the USB adapter and an app call "Stick Mount" to mount external devices (such as flash drives) when plugged into the tablet. I just plugged in my 5D3 to see if it would recognized the storage on my camera. It did not. I'm guessing you will need an app (like EOS Utility) to bridge the camera with the tablet. I too would be interested to see if there is an app available to do this.
There is an Android app called "DSLR Controller" which is still in the beta stage so I have not yet purchased and tested it. It's primarily a remote control app and I don't know if it will transfer images or not. I plan to try this in the future. There is likely an app out there to do what you need, I haven't been pressed to transfer images so I haven't investigated it. Let us know if you discover a workable solution
A note about the Nexus 7 tablet (built by ASUS). Aside from the lack of an SD slot, this tablet is about perfect. Very fast processor, gorgeous display, and excellent battery life for a small device. I travel a lot so I use the USB adapter to connect a flashdrive for watching movies in the air.
A few links you might find useful
For rooting, just google there are a ton of sites and always being updated
OGB to USB adapter (you will also need an app like "Stick Mount" to make it work)http://www.amazon.com/gp/product/B008MS9Y4K/ref=oh_details_o09_s00_i00
The perfect casehttp://www.amazon.com/gp/product/B008FLYROG/ref=oh_details_o02_s00_i00
Tiny Flash Drive (not fast but nice and compact and you can play movies directly from the flash drive)http://www.amazon.com/gp/product/B00812F7O8/ref=oh_details_o00_s00_i00
External speaker (while in hotels I use this if I want to watch movies from the device, It's a little nicer than the built in speaker. I also use a 3' extension cable)http://www.amazon.com/gp/product/B008Y5GHCI/ref=oh_details_o08_s00_i00