You are able to get a design to come back and be flyable/salvagable about 50% of the time doing the following:

Create design
Make a docked core on that design (or docked anything)
Load it
Go to test sector
Suicide
You will now see one of three things:

The docked ship is now ghosted without its mothership on the shipyard and you are unable to get into it. apon relogging it will teleport to 2 2 2 (See here)

The docked ship will be floating out in the sector you are in and you can get into it and fly it around like a normal ship (likely where blueprints spawn)

The docked ship will be floating at the shipyard unghosted and you can get in it and pick it apart

All of the above is random and if nothing happens check 2 2 2 as this is default spawning point for the game.

This is part in due to the docked ship not being able to find its mothership (now despawned since you left the test sector)

You can get the desired result about 45% of the time (I.E Not ghosted and in the same sector as you so you can take it apart)

This leads to the obvious dupe bug for anyone trying hard enough (Thus high priority)

My 2 2 2 sector after testing this for about an hour http://i.imgur.com/YlH75Wf.jpg

Please note that about 30% of the time the mothership is also duped though i've never seen the mothership inside of the shipyard's sector (as seen in the screenshot)