As promised in the thread from yesterday, here's the very beginnings of a plugin manager for Sketch. It's extremely basic right now, and neither the interface nor the code are very pretty right now, but I think it could potentially be useful (at least until Bohemian Coding puts out their own solution!).
I'm going to continue to make improvements in functionality, as well as polishing up the interface and the code as well (which again, is all very sloppy right now). I hope to have it in a much better state after a couple more evenings of work.
Let me know what you think! And please feel free to get involved if you'd like!