The SMALLEST shoulder bag that will hold the following:

[kxl]

Either (A plus everything in C) OR (B plus everything in C)

A. ZI with attached lens + two other lenses

B. D800E with attached 24-70/2.8 AND detached SB-800 flash

C. 8 inch Android Tablet, batteries, iphone, a few rolls of film or SD cards, lens cleaning cloth, blower, and other small accessories.

I think the TT Retrospective 7 would be a candidate, as well as the TT Urban Disguise 30 or the Suburban Disguise 30.

Other options?

 

[slidesandthecity]

IIRC the 'Billingham for Leica' bag was more spacious than one would expect from a bag with such a small footprint. M + 50/2 and F2 + 28/3.5 was no problem. There was (in the main compartment) still enough space for a moderate tele and the front compartment should be able to hold film and your phone. Unfortunately, I forgot whether it also has a zip pocket on the backside. If it has, your tablet could go in there.
The downsides of this bag are: The price (it's worth it, though) and that Leica(/Billingham?) went a bit overboard with padding as they attached non-removable "flaps" to the internal dividers. These are supposed to protect your equipment from the top and are quite annoying if you want to get something out of the bag real quick.

 

[f16sunshine]

Shibata.

Last weekend for a gig. I had 5Dii with 1.8/50mm mounted and 2/21 plus 2.8/100 zuikos, ex430 flash and two spare batteries.
Plus x100 and two spares. You could still put the Tablet in the front pocket which I had an of camera flash "coilly" cord.
Or slide it in behind the removable padding.

Nice little bag.