You can buy split-flap clocks at MoMA [0] for $650. Not cheap.
If you want to see a big one in person, the TWA Hotel at JFK Airport in New York has the original split-flap departures display made by Solari di Udine [1] (the same company makes the MoMA clock). Solari also makes other split-flap devices [2].
Not to get off on a tangent, but the TWA Hotel is a very cool place to visit [3].
[0] https://store.moma.org/for-the-home/home/clocks/solari-cifra...
[1] https://science.howstuffworks.com/engineering/architecture/t...