256GB SSD in 1.8" with LIF connectors is so horrendously expensive it would end up raising the price point of the higher model by a substantial amount. Can't see Apple raising the price point again without a chipset update. It'd drive away users who have been drawn to the unit by the price decrease.
I think it's 100% POSSIBLE that the new high-end MBA rev C has NOT yet been released. It would be MORE EXPENSIVE for certain if it had a 256 GB SSD and 4 GB RAM. I think we could see it BEFORE Arrandale chips! I believe it just wasn't ready in time and the current high-end will be the low end.
I give it a 50/50 shot that we see an added high-end before Arrandale. I also believe that we could see a revised rev D MBA before Arrandale even. I think Apple would still want to take advantage of Nvidia chipset and GPU with the same C2D 2.13 GHz CPU... I think it's 50/50 on it being rev C high end or rev D and changed with the 3G card, glass trackpad, and all the component upgrades...
I would think that the recent rev C "update" was NOT the real intended update for the MBA. I think we see a new MBA, even if called a MacBook before the MBPs are updated again. I also believe it could include a 15" version as a high possibility... still not probable.
Capitalizing on the "MacBook" brand and moving forward with the technologies learned with the MBA makes sense. Also, Apple is definitely moving towards optical drive-less Mac notebooks and the MBA form factor saves so much weight and space less the dang optical drive.
Importantly, a series of MacBooks that also include an external optical drive, in both 13" and 15" models make so very much sense for the "CONSUMERS" in the market. EVERYONE loves the MBA when they use it... the RAM and SSD updates are the final pieces to the project that make it powerful enough and large enough drive. Also, it cannot cost Apple too much more to make an MBA than a MBP in the same size. The drive sizes would probably include a 128 GB SSD and a higher end 256 GB SSD for more money or in the high end.
I really see this happening before Winter! It could even include an OLED display. One more thing... the reason I am convinced it happens BEFORE Arrandale is the dispute between Nvidia and Intel. Apple cannot put a discrete graphics card in this Mac notebook. And, Apple CANNOT put the worthless integrated Intel graphics... so Apple may really want this particular Mac notebook done before that dispute happens... It would DEFINITELY include a Core 2 Duo CPU... assuming that is correct.