Hopefully this saves someone some time, OP may want to update post to indicate that this works (at least I assume it does) on the MDK build and not ME7. The link posted by Dalvik-Cache does work (confirmed as of 9/25) for root access on ME7 but to my knowledge, and I searched high and low last night, especially after bricking my ME7 S4, the bootloader is still locked, the only custom recovery option is
SafeStrap from one of the XDA devs.
The only ROM I know of, I'd imagine there are others, is
Hyperdrive ROM, but theoretically anything that's based on the stock kernel should work. Do NOT forget to re-flash the stock kernel after flashing the ROM of your choice. Also, as it turns out, there's a very good reason to check the MD5 of the ROM before you flash it. I tried 5 or 6 mirrors before I got a matching copy. If your MD5 doesn't match, you're probably going to boot to a black screen.
WARNING!!!
If you plan to try this, read the SafeStrap thread thoroughly. DO NOT forget to select ROM slot 1 (vs stock which is the default when you first launch it) or you will brick your phone. It's recoverable, but you'll need ODIN, the PIT file, and a working stock ROM. The ROM was the hardest part to find, I tried three different hosts before I found a version that wasn't corrupt. I'll get the link from my laptop and, if I remember, update this post with a link to the working ROM for any unfortunate enough to be in that situation.
Feel free to reply or PM me if you have questions, I'll do my best to help you out.
Edited on 9/27/2013 @ 7:38 MDT (8:38 CDT) - Got the custom ROM flashed and working. If there's any interest I could do a complete step-by-step write up.
