I'm pleased to say I got my mining rig working with a Nexus 7 running Butterfly Labs Easy Miner[1].
The specs on Easy Miner say you need a particular kernel to run it - I tried to install it but couldn't get it working on both Nexus 7 (ver 2/2013 and ver 1/2012. It just caused the new 2013 Nexus to hang on startup and seemed to do nothing at all to the 2012 version.
You need the kernel to enable support for using an OTG+Charging cable (it's an OTG cable that's split so that you can use a regular USB connector with the Nexus 7 and charge it at the same time - you obviously need to keep the Nexus 7 running 24x7 when you use it to manage miners).
So I took a chance and went with Cyanogenmod 10.1 on the version 1/2012 Nexus and installed Easy Miner. It worked as soon as I plugged in the miner! The Nexus charges (and stays charged) while the miner is doing its thing.
The only issue I found was that the screen had to stay on because pressing the power button would put the Nexus into sleep mode and kill/stop Easy Miner. I solved that problem with an app that keeps the Nexus from sleeping but also turns off the screen [2].
I didn't have any luck trying this with the new Nexus 7 (2013). I did get a really good deal on the old Nexus - about $120 off the retail price - making this a good way to go to recover the cost from mining.
[Just to be clear I am not mining using the Nexus as the miner. The Nexus runs Easy Miner which uses the miner to actually do the mining. Easy Miner handles the connection to the mining pool or just manages mining, depending on how you have it setup]
Tip when you install Cyanogenmod 10.1 - install it from recovery [3]
Tip for getting everything working - do it under windows and use Wugfresh to unlock, root, copy stuff over, and even recover completely to factory settings. [4]
I have been lurking here for a while and have learned a lot, so I wanted to start by saying Hello and giving you some good information now that BFL is shipping.
[1] - Easy Miner on the Play store:
https://play.google.com/store/apps/details?id=com.mr.app.ui[2] Screen Standby # Root on Play store:
https://play.google.com/store/apps/details?id=com.nkahoang.screenstandby&hl=en[3] Installing CyanogenMod from recovery (go to that section on the linked page):
http://wiki.cyanogenmod.org/w/Install_CM_for_maguro[4] Wugfresh
http://www.wugfresh.com