We parallelized with multiple filers. We used to have one F740, then two, then upgraded those to two F760's now, soon to be three, and have an F8xx upgrade on order for one of them. Oooo, can't wait for that puppy! (Sorry...under NDA...can't say anything about the specs.)
Based on various reports that have come out, we know they are Intel based, support at least 3 and probably 6TB by the end of the year, have roughly 2-3 times current performance, and have something like 1-2GB of RAM and a *lot* more NVRAM (rumored 256MB).
Bruce