Motorola has posted a High Performance Host Microprocessor Family, Today and Tomorrow PDF -- a presentation from the Smart Networks Developer Forum 2003 (June 4-6). In it, they describe some upcoming technology for the PPC.
On Page 33-34, they describe a Dual core processor being added to their roadmap ("Classic" PPC with Altivec, Capable of going up to 2GHz), as well as integration of DDRI, DDRII and RapidIO.
"Multicore" processors have been a long-rumored feature of the mythical "G5" processor. However, as a reminder to Motorola's focus, one of the Mission statements of the Computing Platform Divsion is "Provide the highest compute density/performance within the power budget for the embedded markets (<10 Watts)." Readers should keep in mind that this was presented at a conference focusing on embedded markets.