Yeah ofcourse it has a very small chance by now, we are around diff 0x0000000000000000 8d7c776de8f52815420ca164e661e062c8590ca248c8d4ec which makes it about 16^48, but the hashrate is increasing, so the diff does. Every difficulty doubling halves this number. The difficulty doubled every 2month so far, which will probably slow down at a time, but if it keeps the tendence after 20months it will be just 16^38 which is still a large number, but way less then what it is now.
But after all, I was just curious what happens if we get the same hash number, how does the protocol and how does the current wallet implementation react ?
Edit : laanwj answered it : The first thing AcceptBlock() does is check for duplicate block hashes and reject the block in that case. The blockchain will not fork, it will just not be accepted.