I've had two long-running Rolemaster campaigns. One was set in Greyhawk and used a mixture of (TSR) D&D and (ICE) Rolemaster materials to flesh out the setting and scenarios. The other was set in Kara Tur and used (TSR, WotC and 3P) D&D, Bushido, Palladium and Rolemaster materials to flesh out the setting and scenarios.