I don't know about a spinning one (seems like a waste of processing power to me), but you can put a standard one, or a check mark, or whatever else you want in your title bar, with Visual Prefs. 
I used to run a much larger spinning boing ball anim in the bottom right of my Workbench back in the 90's. I loved it, I used it like a CPU load meter, as when something hammered the CPU I could actually see the anim slow down and then speed up again when the load was reduced. It only ever used a slight amount of CPU as I set the priority fairly low on it so it was no problem. This was on my A1200 with 8MB Fast RAM. It was a very fluid anim. You could load your own into it as well.
