An update, and a picture.
My ambition is to get a platform capable of flying a Sony A7RII for stills photography by the end of March 2016.
I do not expect to be a professional quality flyer by then, all I am hoping for is to fly that, take good stills and land it in a place far from any other person so with minimal safety worries for others at that time. The main risk will be to my wallet and pride. I need to get the camera to about 500'
What I've done since I joined in August is
1) Learned manual flying with a little indoor drone, largely manually, its supposed to be stabilised but hey... you have to be on its case continually with both sticks to keep it in the air. I'm still not entirely comfortable with rotating and flying it in every direction, so still learning, but its fun. The only problem is I'm banned from our highly suitable converted barn because it terrifies the cats.
2) Investigated how to remotely control the Olympus Air 01 camera.
This is a 'lens' camera just about identical in capability and quality to the DJI X5 camera but as a stand alone module its inexpensive. I have this controlled via an Android MK808B TV stick that has HDMI out. I have gradually come to the conclusion that the fact that this camera does not have a wired interface via USB, but requires control over either WiFi or Bluetooth rules it out for multi rotor use. This is due to a decision I don't understand by both Sony and Olympus with these camera modules, they have aimed them at mobile phone use and seemingly crippled them for hacking for aerial photography use. The MK808B is an incredible little device, the guts of a quad core android phone but only weighs about 29g with Wifi built in, HDMI out etc etc.
I'm concerned that on the multi rotor I might get interference between a) The main radio b) the video transmission for FPV and c) the small network between the MK808B and the Olympus camera.
I have also investigated a Raspberry Pi for controlling the Oly Air but it has the same wireless limitation but lacks the Android libraries that handle the live view transmission from the camera. On the other hand the Pi has its own low res camera that weighs almost nothing. I am considering using the Pi and its camera as the FPV sight and maybe then firing the high res camera separately. There is actually a physical switch on the Olympus Air, one option might be to rewire that to my own small board and then setting the camera up prior to flight with a predefined mode.
3) Started buying components to play with.
I bought a Tarot 680 pro hex kit and more recently a DYS 3 axis gimbal, both with the Olympus air in mind. I haven't built the Tarot because I've been uncertain whether to put the E600 or E800 DJI tuned motors on it. I was thinking the E800 but now I'm tending to go back to the E600 as I'm considering forgoing the Olympus Air for this machine and just build it to learn more. I have the Raspberry Pi and could use that with its low res camera just for the fun of things. It might be a good starting point. I may just use the gimbal and Oly for remote controlled photography for wildlife if I don't try to fly it.
Today I ordered the FrSky Taranis as it seems to have the capability for hacking control e.g.: up to the MK808B or a Raspberry Pi which ultimately I expect to use a a camera controller.
So while this is all a bit random, I'd be interested in any thoughts people have. Should I be so worried about having either an additional wifi or bluetooth network on the machine in addition to the FPV video? I don't mind if interference meant I lost visual but I'm more concerned about potential interference with the flight controls.
Next steps
Forgive me if I ask questions that are really my own to figure out, some of these are questions I just ask myself, I don't expect others to necessarily know the answers as I haven't provided sufficient information to answer them.
I need to decide on video transmission back to the ground. Is there a good tutorial explaining the various options for FPV? I see DJI has the lighbridge product and claims 1 mile range while some other systems only claim a few hundred meters. But lightbridge seems designed for integration with their own product range, not necessarily with a mix and match approach.
For a camera the size and weight of the A7RII how large a multi rotor would I need? The camera is smaller and lighter than a conventional DSLR but heavier than a 4/3 camera. I would be using lightweight prime lenses of around 20-55 mm focal length. I would want a set up where I can rebalance the camera with the chosen lens, all the lenses are very light.
I would want flight times of around 10 minutes.
I would want FPV range of about 1 mile with line of sight.
Goals
1) End of December 2015 : Build an experimental machine with all my radios, computer etc. on board to learn how to integrate the components.
2) January 2016 : Start build of A7RII capable platform.
3) End March 2016 : Capable of flying A7RII on short missions in remote region with low third party risks.
Something I can test to see how it all works as I have the camera and the control computer already. 
