As a minikernel? Definitely feasible, though I would make it a separate code base than this minikernel. I'll give it a try.
Edit: One limitation to keep in mind is that you will need to have your own functions for changing the value of the second score. You won't be able to do e.g. score2 = score2 + 100 and have it work the way you would expect.
Yes, a minikernel would be awesome. I think functions for score2 could definitely work. As for color, personally I think it could just be static. My understanding from a few pages back is that a second score might cost some variables, so I'm not sure one for a second score color would be worth it.
Thanks for looking into it!