My personal games have the &dsDryDock do that + sell "dock items" ( basically I robbed the Adventure Outfitters and stocked the station so you can get whatever comes up for that system )
but instead of holding onto your old reactor until Hell Freezes over and you can sell it : the &dsDryDock will either buy it or comp you for it on your purchase ( the comp thing I forgot how to do, so I just have it buy the reactor off you )
One interesting note : Corporate Shipyards : I never set them up in .xml but they use the &dsDryDock and ONLY sell reactors
I always found that cool .-------------------------------------------------------------------------------------
The Regular station screens for category / sub-category :
the dock items / non dock items is cool :
makes it faster to grab stuff and get back in a fight..
but If I am looking for , say, just ammo , I don't want to scroll through a dozen guns and launchers......
could just be me being spoiled by the Merchant Emporium Mod ( which I adjusted for my personal games because of this ) , but it was a thought