Never going to fit in the air. They couldn't even fit one in the 13 inch Macbook pro.
They couldn't fit one or they didn't include one? BIG DIFFERENCE!
In reality, they fit a ThunderBolt chip which is the same difference.
If Apple wants to, it can easily include a discrete GPU. Especially since Apple has switched to AMD, they have 7W discrete GPUs that would rock the Macs with slightly more power requirements from even better GPUs. The big thing is costs, and Apple could have dropped the ancient SuperDrive from the 13" MBP to put a high-end AMD discrete GPU if they wanted... that takes a lot of space.
The big thing is energy requirements though, and with ULV Sandy Bridge CPUs overclocked with a disabled IGP they could make it possible. There was a rumor last year that this is exactly what is happening. AMD's low end discrete GPUs paired with a ULV SB CPU overclocked as essentially using all power for CPU and none reserved for the IGP would make a heck of an MBA.
The thing is people want to assume that Apple has to do the same thing with the 13" MBA as they did with the 13" MBP, but that just isn't a requirement. The big difference is the MBA currently uses a low voltage CPU. In LV and ULV SB CPUs the IGPs are running at worse than 1/2 of the standard voltage CPUs. That really creates a problem in my mind. It is possible that Apple could use LV in the 11" MBA and standard voltage in the 13" MBA as that would make the situation better, and it wouldn't be too far over the current TDP used.
There are better solutions from AMD, and I wouldn't discount them in the MBA. It needs something different if it cannot use a standard voltage CPU. Sandy Bridge isn't the answer. I think Ivy Bridge will at least be closer to the Nvidia 320m, but it's a year off. There have been rumors about an AMD CPU in low end Macs, and there is a possibility that Apple can use a discrete GPU in the MBA. There are many possibilities, but Ivy Bridge is the most realistic and in my opinion Sandy Bridge is more realistic than Arrandale but still a disappointment compared to C2D and Nvidia 320m pairing.
I think Apple sells nearly as many MBAs by keeping C2D and Nvidia 320m as they would by ruining it with SB and potentially damaging the brand as they have before when using an Intel IGP.