Here are some of the links I have for IOPS calculators on my site:
Some useful information on some of the graphing I had done with SQLIO measurements
Testing Disk IO in Linux
This page contains RAID calculators, IOPS calculators and other estimatior tools to use for raid disks and disk arrays. If you know of other calculators, please leave a comment and I’ll list it here. Thanks!
Update: I have an Excel workbook “cheat sheet” that I use to do quick calculation
RAID, IOPS, MBps Excel Cheat Sheet
Great resource for calculating IOPs from a given RAID configuration and also calculating needed disks for average IOPs.