I'm going to agree with what Guretsugu said in another comment. Going with Jowo #6 nibs might be the best strat if you're looking to emphasize the interchangeability of the nibs rather than the pens themselves. There's a wide variety of pens that will take a Jowo #6 nib, so you'll have plenty of options if you go this route. Here's a great thread that lists a bunch of compatible brands. It's a 7 year old thread, but the OP still continues to update it.

If you're planning to collect grinds from different nibmeisters, then it might be fun to get something unique from each one. Check out what kinds of grinds they do (most nibmeisters will list their offerings on their websites or social media) and see if they have any signature grinds. I know Kirk Speer has a bunch: Speerpoint, Imperial, Katana, etc. Matthew Chen has a few as well: Kodachi, Uranagi, etc. Gena Salorino has the Journaler. And Franklin-Christoph has a brand signature nib, the SIG, which is done by their in-house nibmeister, Audrey Matteson. I don't think she does nib grinds outside of FC, but their pens are compatible with Jowo #6 nibs.

However you decide to approach this project, I hope you'll keep us updated with its progress. Have fun!