You might look for something like a Matshita drive. Give me a bit and I'll try to find what I'm looking for and edit this post.
After a little looking, Sony oem'ed this drive from Matshita Panasonic (model Matshita UJ-810). A suitable replacement looks to be the NEC ND6650A.
Does this link show the picture that looks like the back of your current drive? http://us.st12.yimg.com/us.st.yimg.com/I/netcomdirect_2021_17834673
http://www.google.com/products/catalog?hl=en&safe=off&rlz=1B3GGGL_enUS292US292&q=NEC+ND6650A&um=1&ie=UTF-8&cid=1938360677610022909&sa=X&oi=product_catalog_result&resnum=6&ct=result#ps-sellers
The above link shows some places you can obtain this drive. Double check though to make sure the connectors are the same, etc. Like you said, it has connectors on one side that is different from other drives you have looked at.
As I find more info., I'll edit this post.