It has not been announced yet, so I wouldn't hold my breath for it. Intel has quite recently updated their SSD lineup with 34nm process, so it could be a while until new products are announced, especially since there are no better SSD drives now, only cheaper ones.
The fact that even Intel's enterprise lineup doesn't have a 320GB model is no coincidence - SSDs are expensive and usually only the most frequently used data - OS, Applications etc can justify the high cost of SSD.
If you really need that much storage - I suggest getting a secondary traditional drive - I run a laptop like that with a 2nd HDD instead of the now useless DVD Drive.
If you really want all of 320GB of super-fast and super-expensive storage, just get two 160GB drives, especially if it's not for a laptop. YOu can put it in a RAID-0 to almost double the performance in some cases.