I'm not from a visa exempt country so I'm 100% sure about the passport, but I thought every page had to be photocopied.. again could be totally wrong.
Nic, to answer your question, as to what we get back, we get a COPR - Copy of Permanent Residence i think, back from Detroit. Then you take that paper and to the border, and officially land as a Permanent Residence. For people from non-visa exempt countries, we also get a entry visa for Canada to allow inbound travelers the ability to get the border, which is why if you're exempt from having a visa for Canada, you don't need to send your original passport, because no entry visa is required to be put onto your passport.
As for me, I'm traveling to Detroit consulate on Thursday and hopefully land the same day, I'm on a bit more of a tight timeline, so I don't want to wait for another month to receive the COPR.