Ralph Gibson did *beautiful* figure study work with Agfachrome 1000 (a transparency film) pushed two and three stops - for the very purpose of obtaining coarse grain.

Now - I would try the fastest color negative film I could find and, push the same way - two to three stops. A danger here (as it probably was with Gibson's Agfachrome) is color fidelity/ crossover.

That wouldn't prevent me from trying it, though.