Thinking of getting a 2bay or 4bay nas soon, how close are we to SSD Nas' coming out? Shall I wait or shall I just get a disk drive Nas?

How aboutThinking of getting a 2bay or 4bay nas soon, how close are we to SSD Nas' coming out? Shall I wait or shall I just get a disk drive Nas?
It will be used for storing and serving media files to apple tv, storage of personal files and back up and also for downloading via nzbs.
Ideally I would like a 4 bay nas due to better raid systems (able to switch and change one faulty hdd without affect data) rather than using raid 1 but maybe 2TB of storage capacity is enough with compromise of a cheaper system.
Size apart. Might be a bit lower on power and maybe noise. You will be limited to smaller capacity drives though form what I can see. And funnily since you started this thread I was offered a Buffalo LinkStation Mini 240 GB SSD NAS to review. Will be interesting to see what a pair of SSD's do to NAS performance.