When PowerPC was first conceived, it was pretended as a RISC CPU so brutally powerful it could emulate
x86 code without breaking out into a sweat. This was going to be a temporary measure to ensure legacy compatibility with existing applications while IBM transitioned its customers onto the new architecture. Maybe few of you will remember this, but PPC (and the "Mocassino" project) were so widely expected to replace the Wintel paradigm that Microsoft went as far as releasing Windows NT for PPC.
A decade later, here we are discussing the emulation of the PPC's fastest component on commodity
x86 Intel chips. Things don't always go the way you expect them to.
It's sad that there's no evidence whatsoever of an "Anti-Rosetta" for running OSX86 code on PPC machines. In a couple of years my current machines (including my Quad G5) will be totally useless and obsolete, with no new software to run, and probably no new OS releases either.

It's even sadder because PPC, especially in the G5 incarnation, is the better architecture.