The 8-Bit Guy (formerly iBook Guy) created an array using USB sticks: https://youtu.be/dougISKs2vQ Action Retro has a video with floppies: https://youtu.be/1hc52_PWeU8 He also references a MacWorld article with Daniel's array: https://www.macworld.com/article/165663/floppyraid.html
Was going to post the Action Retro attempt. Latency is abysmal, yet it's still a glorious thing to see it (kinda) work at all. Need to see if someone can hack together RAID on cassettes on an old Apple II
Two thoughts come to mind, one not serious, one serious.
1. I can’t imagine having to align the counters on all those tapes.
2. I’m guessing this would really only work for sequential reading and writing. In some ways that makes it more fun as the latency would be that much worse.