I'm not sure what to call these grapes other than fancy grapes. "Designer grapes" just sounds a little too silly and I saw the word "artisanal" used by a fast food place a couple of weeks ago so I'm considering that term dead. Anyway... they're not heirloom grapes. These are new. So... fancy grapes it is.
We bought two varieties. The long purple-black grapes are called Moondrops and they taste like grape soda. (Yes, grape soda!) The round green grapes are called Cotton Candy becuase they taste exactly like the fluffy stuff when you first bite into them. These are not some kind of made in a lab mutantfood, they're conventionally cross-bred, and grown and tended to a little differently than your average grape. The company that makes them is Grapery, based in Shafter, CA.
Grapery was founded in 1996 by Jack Pandol, a third-generation grape grower, with the intent of bringing new varieties and flavors to the market. Much of our produce has been bred to be durable or pretty but not necessarily delicious. There's been a movement afoot in recent years to change that. (See the success of heirloom tomatoes.) Grapery isn't going back in time to vintage seed stock but very much moving in that same vein.
Check their website for a retailer near you!