Yeah great, but they have only for the GSXR 2006-2012.
I don't know how I didn't think of that before, but my dad owns a small factory in Europe with all kinds of machinery for making virtually anything from metal... maybe I can make specs for him to make me a few. Assuming I measure the stock spacers, what else needs be added to make it a captive? Just a small lip on the side that goes inside, and a bigger outside or what? Same depth I suppose?
Could just put a dab of grease on to get them to stick in while you adjust. Yeah, the can still get knocked out, but they will stay put for the most part.