That's a Bad bad BAD idea. You should NOT be moving the computer like that. When you sleep, the Hard Drive heads are parked. But if you just close the lid and keep the machine awake, they are still operating and this makes the Hard Disk very susceptive to damage. Walking down the hallway would probably be okay, but I would be extremely wary of putting in a bag and taking it to the next building.
What's the issue with sleep? It's near-instant, so I don't see why you wouldn't want to use it.