No youth models but Remington, Benelli and Franchi all currently make a 28 gauge autoloader. As I recall there was a Charles Daly autoloader in 28 gauge too but they aren't very common.
The best one IMO is the Remington 1100. You can either cut the stock or get a youth model stock from a 20 gauge 1100 as the frames are the same size and the 20 gauge stock will fit on a 28.
The Benelli and Franchi are both recoil action guns, are very light and have more noticeable recoil than the 1100. I owned an 1100 to help young and small statured shooters start out. It's a very good gun for the purpose but if you reload 28 you'll find it tosses the hulls a very long distance.