AmigaForever (aka UAE) does PPC support by utilizing QEMU...... 
Cool. If UAE is using QEMU, we have a way of integrating the work on more modern hardware with Amiga emulation.
Cloanto with its AmigaForever, a commercial product derived from UAE, might be hesitant to go that far.
We'll have to see.
Either way, it's X86/X64, not a WiiU. ;-)
Edit - Then again, it could also be PPC on an 11,2 PowerMac or a Power9 system.
You wouldn't run X5000 emulation on an X5000 (and SAM emulation on an X5000 would be silly).
It could open up some possibilities for X1000 owners, but it would be pointless on lower end AmigaOne systems as they wouldn't have the cpu power (come to think of it, neither would a WiiU). ;-)
2nd edit - One step further, if a PCIe G5 could run this type of emulation, what prevents an AGP G5 from doing the same?
The AGP G5 wouldn't have PCIe slots, but we are talking about emulating the hardware, not acting as some kind of translation or wrapper for the platform.
3rd edit - Actually, if you were running Linux and utilizing the extra cores of an X5000/30 or X5000/40, then emulation of multiple PPC sessions might make sense.
Could be a way to use the extra core on an X1000 as well.