I think that people who were really fast, like Cro Cop, and who managed distance well, like Francisco Filho, could've possibly had success against Schilt. Cro Cop's performance against Mark Hunt in 2002 is IMO the best that he ever looked in a K-1 ring. That version of Cro Cop - excellent conditioning, incredible reflexes, lots of footwork and movement, and serious power in his hands and feet - could've maybe beaten Schilt on points, moving around and avoiding his offense and chopping away enough on the outside to score. But I don't know that he actually would've been effective given Schilt's reach and his crazy jab. Unless he landed a perfectly placed shot like he did against Sapp and injured Schilt, I can't imagine Cro Cop scoring a KO with his hands or reaching the top floor of the Hightower for an LHK.
Filho in his prime might've also given Schilt problems because he was very good defensively and his Karate background gave him a great ability to kick with his lead leg and keep people at bay. He also had some of the scariest power that I've ever seen in combat sports, so if he managed to land something on Schilt, he could've turned his lights out like he did Hug, Hoost, and Sam Greco.