At the same time I'm looking ahead to see how feasible the ascent to 38ESR will be. Even money says that Mozilla and Google drop 10.6 support (and quite possibly 10.7 support) sometime in 2015, but if we can stall them to drop it for 38 but not remove any of the code like they did for 16-17 when 10.5 support was removed then we can probably make it. At that point we would exit the 38ESR support cycle in late 2016 when the youngest Power Mac will be turning 10 years old. If we have to drop source parity then, it would certainly not be in shame.
And more good news, this time for Linux/ppc users; at last there's apparently a solution to the infamous bug 961488. If it works, we'll see if it can be uplifted so you won't be out of commission for too long.