Before Nickelodeon launched either All That or Roundhouse, independent producer Thomas Lynch shopped around a teen ensemble series, Kids Incorporated, which was eventually picked up by MGM-UA to be distributed in syndication. The series lasted two years on broadcast television, but was picked up by the Disney Channel shortly after it was cancelled in May of '86, and remained on Disney until 1996. Sadly, reruns remain in the Disney vaults, and rights to the series are otherwise split between MGM & Fox.
Like All That or, way before that, The Mickey Mouse Club, Kids Incorporated was a launch pad for a number of its cast members, chief among them being Mario Lopez (later of Saved by the Bell and currently the host of Extra) and Stacy Ferguson, whom we know better as Fergie of the Black Eyed Peas.
In fact, Stacy is featured in the following clip from season 3, in which she performs a cover of Lionel Richie's "Say You, Say Me" (from "White Nights"). You'd hardly believe that the blonde warbler shown below would later become one of the most recognizable women on the planet more than 25 years later. Kidsincorporated (DUH!) uploaded the clip:
The series alumni also includes another Top 40 star, Martika, who had a brief run on the charts after leaving the show, and Jennifer Love Hewitt (Ghost Whisperer), who flirted with chart success herself a few years back. Too bad the rights are tied up in limbo, because you can bet Disney would put it back on the air in a heartbeat if they felt the need.