Thnx for all comments.
The aim is to make it with the full 2 manuals

I have roughly 3cm on each side space left for wires and so on. The height is not important I already measued that the casing I have here is 10cm higher then the 310 will become so... not a real problem
Makeing it fit is not the challenge. Resoldering all wires is. When I gutted the 2 310's I was in kindof a hurry (I had both for sale back then but noone wanted them and I had to move to this house... space was limited..can't put all 3 upstairs... what should I do? throw away was a shame so I decided to cut them into peices for spare parts and this idea) so I cutted all main wire trees.... Mabye a complete rewire is the better thing to do...
The plan for the pcb's from the back plane is to put them all together vertically or some rows horizontally. I just have to see what space I have left. I always could make a new casing if this concorde box won't work. Ofcource I want the oscillators boards to be enough visible so I can tune the 310.
The pedal and swell pedal are not a real problem.
And yes GeeJee... I'm crazy

but you need to have crazy ppl in this world to improve concepts or invent stuff
There is even an older wish for the 310 and that's a total midification ... it's doable but it will cost a whole lot of cash since most keys have 3 or more wires that need to be switched per key. Imagine the number of 4066's (or different IC's (found some that could switch more then just 4/ic)) you need...
Mabye a build-in smallstone and mistress is also a nice touch for a portable eminent

but that's definitive at the verry end of this project.
The reason why it will talke a lot of time to complete is: I have to work each day and give my attention to our little Aurora and my wife... time for other pleasures like making music or doing things like this is, unfortunately, limited.
J.