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.
It's true that TRIM probably won't work, but you will get huge performance boost from RAID in all areas - random and sequential writes and reads (500MB+ read must be nice) whereas TRIM only helps to maintain write speeds over long period of time.
You can already do what TRIM does on RAID by running Intel Toolkit optimisations and restoring RAID array and better tools are already being developed.
Also remember that TRIM only works in Win7 and only helps with write performance after a while, so in some way it's probably better no to rely on TRIM so much.
In any case, if you do decide to build any RAID-0 array - ensure that you have a solid backup for the data that you care about RAID-0 is easy to break, but with 2 x 160GB SSD and the fact that you should leave ca 20% free space for optimum performance, you probably only need 250GB HDD for backup - perhaps you can reuse your existing one for that?