Of course, Dumbledore had weak wards surrounding his house manor. That makes perfect sense when you're number one on wizard-Hitler's list. Oh wait, they're only weak because Dumbledore told Harry how to get past them. ::rolls eyes::

People who completely fail to understand house-elves annoy me. While the books never goes into any detail about how one acquires a house-elf, I doubt you can just buy one (especially not in bulk). House-elves are actually loyal to the house, rather than an actual person.