I have been digging through the code and can now add custom factories to the factorissimo2(F2) mod by injecting into the F2 mod code but then with every update I have to start over again.
I would like to create a new mod dependent on F2 that can define width, height and connections for inside and outside the factory. I could then add technology and recipes.
I have identified where I think the code needs adjusting but have not tested it yet.
prototypes.component.lua needs width and height variables and replace j with w & h
prototypes.layout.lua needs a global AddLayout(name, generator) & make_connection

optional
prototypes.factories.lua could include a generic template to eliminate cwc0() and cc0() calls that I have to duplicate as they're local

If you are interested in adding more factory types to your mod you're welcome to acquire my idea and integrate it as I'm just adding 1 building for now a train station. Not for trains to enter but a factory 40x8 externally and 64x46 internally with connections spaced for train loading and unloading. http://i.imgur.com/DtFLD3g.png I have no art work for it yet.

So This is what I got done in a day (about 8 hours actual work)
http://i.imgur.com/pMjLNBq.png
http://imgur.com/KLK546O
http://imgur.com/VAZPeW9
It mostly works but for a few issues, rotating it while placing behaves oddly, water pumps can't pump into a factory(kinda need that for the station layout to work), power doesn't reach the back of the station inside[64+3 > 60+3]
As I said you're welcome to my code if you want it, I'd appreciate the changes I made in the middle image if not something like it.
Also if you want help/second perspective with "interior upgrade roboports" I'd be interested in what you had planned. :D

Nice, I'll put it on my (growing) to do list.

Any ETA on something like this? Would be so amazing to have it :D

++ Please add my vote too
I love the idea of seeing a Factorissimo train station

Something similar would be great for a hardware mall

+1 for this, is this already a thing @MagmaMcFry?

/update: As far as I can see the abstraction needed would be to enable custom layout generators plus the factory specific rendering stuff in the prototypes. Maybe include the rendering info in the layout generators or make some abstract factoryContainer class that has the layout and the rendering system in it.