1. they won't let you do it. so you will have storage issue. so they can sell extra retainers.
RMT trade face to face anyway.

2. screw housing. tons of people don't have housing of their own. that's a 2.0 features most people in 3.0 doesn't even know about. =p

3. why would they give you shared retainer if they don't want to to transfer stuffs to alt for storage?