This might not be as good as it should be - after all, we can emulate the arcade game well enough on systems way less powerful than the Wii!
However, the code (even though re-engineered from the original arcade games) is very, very slow - the platform I run it on has a 950MHZ CPU with a 110MHz SGX with 256MB RAM onboard and it cannot run the 60fps option without stuttering. Cannonball is purely CPU bound, and doesn't use any graphical hardware acceleration at all - I find that it requires a minimum of 1GHz to run at all well with the enhancements on.
Given that my platform is actually a lot more powerful than the Wii, I'd not expect this to run at all well if ported, and if the only way to get it to run is to remove the enhancements, you might as well play it in MAME.
Would be nice though!
D.