I couldn't find it either. I did come across this thread that was pretty recent (May/June 2013) and the consensus in that thread was that the latest versions of Moonlight and the Media Pack Plugins did not even work and were not worth spending any energies bothering with it.
The thread was titled: Thread: Microsoft Media Pack for Moonlight from a OpenSUSE forum.
_excerpt_
> > Q: Hey guys,
>>
>> Does anybody know where I can find this?
>>
>> Microsoft does not support it anymore and there is no more download link for it, I guess they got scared when Linux users could watch Silverlight media on Linux.
>>
>> Thanks.
>
> A: i don't think i ever got it to work, so not being able to download broken software is not a big deal.