I used to own the black APO version (and subsequently the white APO HS G). My black version didn't have a hood, so I bought a MATIN reversible hood via evilBay (Korea). They're double-threaded and can be reversed using the supplied adapter ring and you can also use filters. It's a very good bit of kit albeit not OEM, worked perfectly and looked the part. Do a Worldwide search for MATIN XXmm lens hood (XX = your lens thread size).
It's the best alternative I know of to the original.