I am not sure why you guys worry about stamps in your passports? In the Instruction Guide, it clearly says: "Provide photocopies of the biographical pages of all passports and/or travel documents (valid and canceled) for the six (6) year period immediately before the date of your application, or since you became a permanent resident, whichever is more recent." Then it goes further to describe what "biographical pages" mean: "The biographical page means the page that has your name, photo, passport/travel document number, issue date and expiration date."
There is nothing about providing stamps in your passport on the CIC website. Unless I am missing something here, and if I am then please correct me.