Quoting Blythe.:" does it slide around and bunch up?"
Definitely doesn't bunch up since it's thick-ish. Kinda feels like a sweater for my strap. I haven't really worn it enough to see any sliding. I'll have to check for that though.
I don't think I would pay for one, but I'd probably attempt to make something similar when I got the time. I'm pretty craft-y, and I like fun stuff like that, but I wouldn't consider it important enough to buy one from someone.