For your Super Sherpa, there's also a Happy Trails side rack arrangement that looks pretty good. There are some pictures in the photos section in an album labeled "front rack" in the 1999-2003_SuperSherpa@yahoogroups.com
I'm considering it myself, but understand it's not cheap.
I like your metal work. Especially the bicycle tube covering - GREAT IDEA!
I've just got a couple of low mileage Sherpas that I'm equipping as we speak. Can't wait until the weatehr breaks this spring and get out on them.