Remember: it's just a guess....here's mine.
First: remember, this is an artist's rendering. Nothing more than some sort of guess. The only appropriate speculation is how much of a guess it is.
Having said this, perhaps Apple set the following requirements:
Build a consumer focussed product, like the iPad, that is
1. Intel Based
2. Mac OS X Based, therefore keyboard & pointer
They sell a bunch of iPads that have the same amount of external connections: headphone, mic and 1 charging/data port. But I believe that this rendering has it wrong. I'm betting on 1 type C USB port and a Lightning connector, but that's it.
I'm still betting that this will be part of an "either/or" introduction that will see 2 new devices, this one and the mythical 12" iPad. Essentially the same screen, but the iOS version will be pure iPad & a touchscreen. The Mac version will have a keyboard and trackpad. My hunch is that these 2 new devices will have the all the same ports and accessories, the only differentiator is the OS and therefore the input/navigation "stuff". Maybe, just maybe cellular data will be an option on this new Macbook...that'd be pretty cool.
Price range? It'd be nifty to think that Apple will make a low cost/value play, but that is not their style. The lowest 11" MBA is $899 USD, the most expensive iPad Air 2 is $699 USD. Gotta believe that's about where this new tandem will live, call it $799 USD for a 128GB, 12" device, your choice on OS decides the form factor. 2 more storage bumps (256GB & 512GB) and wifi/cellular and pick your color. That's it.