@Felek666 Well... you aren't completely wrong about emulation.
The Wii U uses a Tri-Core IBM PowerPC750 "Espresso" that runs at 1.24GHz, while the GameCube is also an IBM PowerPC750, it's codename is "Gekko" and Espresso is just an evolution of the GC CPU... (btw, Gekko runs much slower at 486MHz and is single-core)
We have a CPU that is pretty similar to the GameCube, at the point that vWii disables 2 cores, reduces clock speeds, locks caches, etc in order to match the Wii's "Broadway" CPU (Which also is a PowerPC750 design).
However... we have the GPU part, I will try to explain this, The Wii U has a chip that is codenamed "Latte", inside Latte we have the GX2 GPU (Wii U Mode) that is the new HD Graphics Processor with a NEW arquitecture, and we also have the GX GPU that is there for legacy purposes (It's probably the Wii GPU).
When going to cafe2wii, Wii U switch to the GX GPU and GX2 GPU stops working, so that's why it's not possible to get highter resolutions in vWii mode, GX has the same power capabilities as the original Wii, no more, no less.
So... the CPU part is easy, you have a CPU that is much more powerful in the same PowerPC family, the process is OK up to there.
But the GPU part is complicated, because you have another arquitecture in the GX2... (It's the only chip that would be capable to run the games at higher resolutions) which I'm not really sure about this part because some people says that the Wii U GPU arquitecture is based on the R7xxx of AMD, and a old email from AMD iself said that the GPU is based from the E6760 core...
Anyway, the only thing that seems to be a problem is the GPU, but the GPUs that are inside PCs are a lot different too, My PC specs are this:
4GB DDR2
Intel Core 2 Duo E7500 2.93GHz
NVIDIA Geforce 9500gt
And I remember I managed to play with normal frame rates Wii games at highter resolutions than the original console.
(DBZ Budokai Tenkaichi 3 is the one example that comes to my head now, I can't remember of a GameCube one)
I don't remember exactly at what resolution though.
What I try to say with this is that the Wii U is capable of emulating the GameCube and play at highter resolutions, the CPU isn't a problem, RAM neither, the only thing is the GPU, but a NVIDIA Geforce 9500gt managed to run the games at highter resolutions, so why the GX2 GPU wouldn't?
The thing I'm about to write is a little cancerogenous, because is not the proper way to measure performance between GPUs, a lot less if the GPUs are from different companies brand, but just take it to get you an idea:
The NVIDA GeForce 9500GT manages about 90GFLOPS if I not bad remember, that GPU as I said is capable of making the Wii games run at higher resolutions.
The Wii U GPU manages about 352GFLOPS (and yes, I know some people says that is 176GFLOPS, but it's bullshit). So, we have a GPU that is more powerful, if Dolphin has to do the job here... well, it's obvious that I will get a decent resolution.
Then summarizing, yes, it's completely possible to make an emulator of GameCube for Wii U, a direct port of Dolphin would run like ass since Dolphin is designed for x86-64 arquitecture, and that would make a problem here... but the Wii U is powerful enough to emulate GameCube games at highter resolutions, however someone has to make FROM SCRATCH an emulator for the Wii U arquitecture and not the bullshit that Pedro702 said about Dolphin running on the Wii U, hell... I don't know how someone can even think about porting a program that is designed to translate PPC code to x86-64... we don't need any CPU translation here, just native PPC code, the real thing that needs to be translated is the GPU part.
The problem with dolphin is also that is not designed to run PPC code as native code for obvious reasons (I think Nintendont do that, it's an interpreter), is not as easy like to port a SNES PC emulator, in that case it would be correctly to port it from PC because the thing emulates completely the SNES, I doubt the Ricoh 5A22 from the SNES would have similar code to the X86 CPU or the PPC to make an interpreter.
But well, nobody is going to make a brand new emulator for the Wii U to emulate the GameCube's games, it would be really hard and I don't think it's worth the effort, as we saw, even Nintendo went the easy way and integrated the GX GPU instead of making software emulation, and others emulators are just ports from PC.