Although it's unlikely we will ever see this crossover, I think if done right the timeline and plot of Pacific Rim could be intigrated into a Toho continuality since very few movies outside the showa era share a continuality. Starting from the 1954 attack by the first Godzilla up through 2010 when the Daikaiju war ends with humanity trying to recover with the breach being opened 2 years later in 2014. In 2025 when the Breach is closed by the self destruction of the Gipsy Danger, the energyreleased by it's destruction caused the DaiKaiju to reawaken. 5 years later a second breach opens and the world governments greenlight the creation of new Jagers, the first 2 being built by Japan, designated "Jet Jaguar" and "Mecha-Godzilla MK4". At the same time, the DaiKaiju of earth reemerge from their 20 year exile to once again wage war fighting Kaiju and Jager alike *except for a few such Mothra and Minilla who are friends of humanity*. However, the Anteverse has birthed a new and incredibly dangerous Kaiju. One at even the Precursers can not control. A fiersome beast who's powers exceed those of Slantern. This new Kaiju is designated as "Bagan".  When Godzilla reemerges to battle this new enemy, will he be humanity's saivor or will he burry us once he is done with these intruders?
I know there are similar ideas floating around the internet, some of which I've drawn influene from. But what are your ideas for a crossover movie be? What Monsters *besides Godzilla* would you like to see appear? Let me know what you think.