If there was a good one I would love it too!
Seriously, it has been tried before, but in the end it does not work.
There is one ray of hope though..... Apple has been toying with an experimental Mac OS X that will run on a PC with specific components. It's codenamed "Marklar" and supposedly runs on an Athlon XP processor system. Now whether or not it will see public release is up to Steve Jobs and Apple. Let up hope it does, as a dual boot Mac OS X and WinXP machine would be wonderful!