Apple is in the first stages of ramping down its existing iMac supplies ahead of new models that should switch over completely to Intel's Core iX line, insiders said Thursday. Resellers have reportedly been told not to expect more shipments of the 21-inch Core 2 Duo iMac, others are being asked to sell all their existing models rather than ask for more. AppleInsider expects new models would arrive sometime within the next few weeks.