I saw Muscat hybrid grapes at the Saturday Pasadena Farmer's Market.this last week. They had a nice Muscat taste though not as intense but with much more edible seeds. I'm not sure if true Muscat Grapes are in season right now.
The vendor is Apkarian Farms. They have some delicious grapes. In addition to those seedless Muscats, they also have (seedless) Thomcord grapes, a cross between a Thompson and Concord.