Boy, that brings back an old cliche about the Japanese miniaturizing everything ! That's taking the old "hard drive" analog clock idea, and sticking it on your wrist:
On the general idea of spinning something, and having LEDs, there are also the old propeller clocks. Close to 15 years ago, I made my first "Propeller Santa" Xmas display. A little time later, I saw one about the size of mine (4' diameter), at a trade show. I spoke to the lady running the booth, and asked if she had problems with people poking their fingers in it, too. She probably thought, I was blowing smoke up her skirt. Now you can pick on up at Target for five bucks:
I bought a similar one, not to long ago at the local TRW swapmeet, for the same price:
In bulk. 500 minimum, you can get that $3.21 price. I tried it at higher volumes, to get a bigger discount, but that $3.21 price wouldn't budge. That's really a slim margin, for committing to that many units. Especially, since you're now competing with Target. May have to sell it for under $5. Maybe $4.