For this link go to the bottom of the page and click on the test 1 and test 2:
"""Some benchmarks made with CacheCade with single SSD show over 40.000 IOPS and with two SSD even over 80.000 IOPS (see interesting test 1 and test 2 results).""
Thanks for that link. Think SSD's in front of the raid array are the way to go. Was hoping to talk to someone who actually had one of these in production to see if they had any issues.