Thats actually an excellent Idea... I wouldnd be suprised if you saw the big promotions getting together from there respective sports putting on a joint effort

Imagine if the UFC(Providing there was a quick way to assemble the cage) and lets say GBP got together on May 5th and brought us Mayweather vs Delahoya and Quinton Jackson vs Chuck Liddell.. with an additional Boxing match and MMA fight on the undercard

The money generated that night would be so friggin obscene it would be amazing