> though computation time is still an issue

This is what I got hung up on. I was doing some independent research on real-time cloth simulation for sailboats and I reached the conclusion that the physically accurate techniques are not real-time. I was looking at simulating tensions applied at specific vertices of the sail, the stiffness of the cloth, wind pressures, etc... and I gave up on finding anything that was doing it in real-time.

Am I wrong? Or is there a SIGGRAPH paper I haven't found yet :P

Have you looked into Small Step XPBD (introduced in the paper "Small Steps in Physics Simulation ")? It's the most efficient nonlinear dynamics integrator/solver I've come across, and luckily one of the simplest, too! (Keeping in mind that simplest nonlinear solver is a relative metric.) I've been able to simulate very stiff materials like bone by updating the sim at 6000 steps/second. The exact number of steps/second you'll need will depend on both the desired spatial resolution and physical accuracy of your sails, but I wouldn't be surprised if 6000 steps/second is more than sufficient. And computers are fast enough where you could simulate quite a few large, detailed sails at that rate in realtime.

Thanks for that link, I had not seen this paper before. I will add this to the backlog of things to try!