This was a definite design decision on the part of Apple, however. There is only one drive slot as well, so again, internal drive bay expansion is limited.
The base option is 256GB, configurable to 512GB or 1TB upon purchase. The downside is the internal SSDs are of limited size. This is definitely one of the faster options that will be available on the market. The 2013 Mac Pro will come standard with a Solid State Drive (SSD) connected via a PCIe port for faster data transfer rates as compared to standard SATA III.
