Apple CEO Tim Cook said last year that there will be a new Mac Pro this year, so there is little reason to think otherwise, and what interests me more is when it will arrive, and what it will offers in terms of size, cost and performance.
One viable rumor is an option of 2TB SSD drives, perhaps related to Apple's acquisition in January 2012 of Anobit, a designer of flash memory controllers.
One fantasy is using the speed of Thunderbolt and its PCIe side, or better yet the faster next-generation optical version of it, to eliminate the need for a huge amount of internal space for additional drive bays and expansion slots. Instead, a smaller, lighter main unit could be designed to work with fast, low latency external drives and PCIe expansion slots in off-board boxes. I would also be happy to ditch built-in optical drives: for their now far less frequent use, an external one in the drawer is fine.