Not exactly. Closest we have is https://nosli.vercel.app/

But there's no character limit on notes here. So is it really needed?

#MillionSatsIdea right there!

It was there last year, according to nos.today https://nostr.band/note15uzys329fef4tr8lyht5m72de47sdmht2pqhs2edqxgpgj3hqxdslt07tj

Satellite is designed for reading threads. https://satellite.earth/thread/note1st7a2et72nxl4nzhxj2nx7w4q8ptgumurwy8cu7m8zpv3swnne8q7yfr2w (this thread)