They are made by Quantum for Hummer:
http://dev.qtww.com/home.php?cat=297
You can get the steps on ebay lots of the time:
http://cgi.ebay.com/ebaymotors/HUMMER-H2-SPECIAL-EDITION-aluminum-side-steps-set-of-4_W0QQcmdZViewItemQQcategoryZ33650QQihZ006QQitemZ1 60164411615QQrdZ1QQsspagenameZWDVW
I purchased a set for my H2 from Quantum with their wider flares as shown in this thread:
http://www.elcovaforums.com/forums/s...t=29825&page=2
The should fit over the OEM rocker protection bars, but you may need to fab up some braces for the bolts to mount to. They will stick out really far and not sure they would look good on the 3 unless you had a wide wheel/tire combo. I have 13.5" wide tires on my 2 and the steps stick out the side as far as the tire does!