Just stumbled on this thread, we have 4 16 bay infortrend 4gb chassis. I have tested 16 disk RAID 0 128k & 512k stripes and have never really saturated the port. I get around 280 write, 350 ish read using AJA 1080 10bit, 8gb speed test.
I also get similar numbers as RAID5 and 8 disk RAID5 on the same unit.