@ strobe
Well, I follow the links ;-), and I see this:
The MPC7447 is manufactured on Motorola's 0.13-micron HiPerMOS silicon-on-insulator (SOI) copper interconnect process technology, enabling it to deliver superior performance over bulk CMOS technology. In addition to increased performance, SOI technology offers excellent low power capability, making the devices ideal for embedded applications in the wired and wireless telecommunications, networking and imaging arenas.
The MPC7457 is manufactured on Motorola's 0.13-micron HiPerMOS silicon-on-insulator (SOI) copper interconnect process technology, enabling it to deliver superior performance over bulk CMOS technology. In addition to increased performance, SOI technology offers excellent low power capability, making the devices ideal for embedded applications in the wired and wireless telecommunications, networking and imaging arenas.
When you continue to read those pages you will see that these really seems to be the same chip, except for the L3 cache support (I guess the key is the last "7" in the model number)! :-)
Very nice if you ask me! :-D