One way is to obtain a rogers or fido number, then switch it to PCM,

I do not think there is any way to do that because the sim card is bound to the phone. Just my guess.

I tried and failed with SO.

Here's the problem. SO's (and PCM's) phones come with SIMs that have phone numbers pre-assigned. The sticker on the box indicates your phone number. That way you don't have to explicitly activate the phone; just start making calls and they know that number is now in use.

Suppose you want a particular number. You call it and there is a fast busy. Even if SO/PCM would be willing to give you that number there is no practical way for them to do it. Somewhere, in some 7-11 or P-C store there is a phone with a SIM that has that number. So, assuming they even know where that phone is located, they'd have to recall it, change SIMs to reassign it a new number, return it to the store, etc. — all in order for you to get a vanity number. Good luck with that

I had grand visions that SO/PC would at least have a list of #s that they know are already distributed in SIMs or activated and then a list of #s that haven't been used yet.

They must already keep a separate pool/list of free #s for moves/lost #s/transfers, etc. I was hoping that my vanity # would be in that category or the "not on a SIM yet" list. No such luck tho. When I called in, CS didn't have even have control over that pool of #s. The computer tells them which number to give out.

Some of those SIMs must come back to the "factory" anyways. I would assume phones returned to the store would have to go back, plus the older model phones that didn't sell would get returned. However I would assume in those situations (after testing/reprogramming/whatever), the SIMs would just reused into the new phones they ship out.