I Think that you miss the point on that sizes screen the gameplay sucked . The review one. On a tablet that gameplay would be great. But without a fan brazo isn't for tablets.
In that price range and size, mobile gaming is not going to be relevant for the products; at least not in the traditional types of PC games you are thinking about. I don't think anyone really sees them as any "gaming platform", certainly not AMD themselves. A brazos platform system might be able to do the occassional Cataclysm on the road, but no one is going to rely on an ultra-portable to be their regular gaming rig.
For serious mobile gaming, I mean systems that are specifically aimed , or really any high performance application, the only real choice you have would be a nehalem/SB based CPU + GF114/Juniper/Barts; everything else is going to be infeasible or a sub-optimal experience. Something like this would be what you are looking for:
http://hothardware.com/News/Acer-Introduces-HighPowered-AS8950G-Gaming-Laptop-At-CES/
Even on the more midrange performance laptops that can run some 3D apps at a reasonable clip, AMD won't have any credible answer until Llano arrives in 6 months.
The only saving grace is power usage . Thats a big deal. Intel can come down there and more than compete on performance and price if they desire. Force AMD to sell at cost. But Intel I doubt can compete on powe usage well see . I have yet to see anything on an 11 " screen for oaktrail . But it may have way better graphics than we know.
No, Sandy Bridge does not really play in that space either, given the manufacturing cost alone in terms of the both the die area and the cost of the process node; it's not even in the same ballpark. Also there is the fact that they will not have a sub-15W chip from that uarchitecture any time soon.