Left angle Micro USB OTG cable with charging

So I am trying to put a Nexus 7 into my car and my setup is a little different. Many people have used OTG cables with power to be able to play music via DAC while still charging their tablet. My only issue is there is no room for a USB cable to stick out of the tablet unless it is angled. Every single OTG cable WITH power that I can find is straight out. I have found left angled ones that do not have power but not one that has both power and the angle. The setup I am wanting to do is basically this (not mine):

h ttp://i.imgur.com/Y3omDV8.png (stupid site won't let me embed or link to anything yet, sigh)

The only difference is I need it left angled. So, I have 2 options:

1. Find an OTG with power that is left angled. So far I have failed at this. I found ones that will power the attached device, but not the tablet.
2. Can I put a normal USB left angled cable into the tablet and then plug an OTG with power into that? I assume by putting a regular USB cable in the middle, the OTG stuff would not work, yes? So I would a need a left angled micro to micro USB OTG with power cable for this option to work... which seems even less likely to find.

Am I missing an easier method here?

Thanks!