Jan's stuff (from stitches n' stuff) is always a winner. For those in the Pacific NW -
In the Portland area there is always NW Sewing
. She is a good person and a whitewater enthusiast as well. Her slings are ~$45 depending on materials and sizing/design
I had her retrofit my cat floor with some cam straps for extra strength and rigging options and she did it cheap, fast and well.
She also repairs drysuits/tops/pants and tents. I'm in talks with her right now to make a silnylon wing for me.