Speculation is circulating that suggests one hole is for a rear-camera and the larger opening next to the dock port is an SD card slot. An SD card slot would render Apple's own Camera Connection Kit an unnecessary duplicate, so take it with a grain of salt.
Another rumor is that the rectangular hole isn't an SD card, but for a larger speaker. It's a possibility, but judging from Apple's iPhone and iPod touch designs, Apple's never been keen on cutting a big hole for a speaker.
If the case is legit, we'd start holding off on buying an iPad for the moment.