Thanks to NTT DOCOMO, some recent leaks were answered. First, it was the LG Optimus G Pro and now, it is the Sony Xperia Tablet Z. Based on the information from NTT DOCOMO, Sony Xperia Tablet Z will arrive in mid-March 2013.
As what was leaked earlier, the Sony Xperia Tablet Z is dustproof and waterproof. Here is a picture of the tablet.
What is not clear is the dimension of this device. Based on the previous information, it should be just 6.9mm thin. So, now we know that NTT DOCOMO will have this tablet from mid-March 2013.