American girl did have a tent-it retired about 3-4 years ago. The lower 2/3rds of the tent was yellow, with the upper 1/3rd black. It had a fuchsia-colored accent ribbon that said American Girl and had bugs embroidered on it that bordered the two colors. The tent poles were aqua and there was a matching black fold up chair with the same ribbon as the tent. There was also a black and aqua matching mummy sleeping bag that was sold seperately. I think what you may have found was one of the Our Generation tents from Target.

The AG sets come up once and while on ebay, but the tent poles are not always included-I've heard they broke fairly easily. HTH.