My nephew was able to play on the grass court(s) in the JW Marriott Desert resort in Palm Springs. They have three, but phase them out to keep the grass in good condition.
He said it was excellent. Didn't notice the ball being too much faster, but everything died on the grass -slices bounced two inches off the ground.
It sounds fun. I'll have to get out there myself.
They let him play on it for free during a tournament there.