Use items from your bank outside of it (Video)

1. Open a trade with someone then close it.
2. Type this: /run TradeFrame:Show()
3. Go to your bank and drag some items to trade window's slots
4. Now you can close all windows and go away.
5. After that you can mail these items, put in guild bank or void storage and use for transmog.

This will persist until you logout or get a loading screen.