I actually read an experience story on another board from somebody who "landed" in Canada Place in Edmonton (government offices building downtown). He had heard that you could, phoned the call centre, they said no, he went and tried it anyway and found out that he could but the requirement was that you had to have lived in Canada for at least a year which he had so they processed him. If you live close to the border, no big deal but if it's quite a drive, it might be worth it to ask your local immigration office if you can "land" there.