> The PPE is a 64bit PPC with G4-ish performance

What is "G4-ish performance"? Keep in mind that the fastest G4 is about 6 times as fast as the slowest G4 (based on clock rate).

> TI do processors with Cortex-A15s combined with a set of DSPs. IIRC Freescale
> do something similar with PPC cores.

Indeed.