Okay, so here's some useful info:

Each ship has what's called a "seed" - a 16-digit identifier prefixed by "0x".

For example, the seed for the Horizon Omega is: 0xC4C9C1AABCA59FE6

The seed references the physical configuration of the ship - parts and colors - but not the number of slots.

If you had a 48-slot ship but disliked its appearance, you could change the ship to a Horizon Omega by using a save game editor to change its seed to the above value.

You can get the seed for your current ship by using a save game decrypter or editor.

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No Man’s Sky Save Editor:

http://www.raxdiam.com/nmsse/

http://nomansskymods.com/mods/no-mans-sky-save-editor-beta/

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No Man's Save - Save encryption and decryption (EXE + source code)

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Seed Changer (Ship/Multitool Changer)

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You might need Microsoft .NET Framework 4.6 if the above tools aren't working for you.

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Browsing Seeds:

169 NMS Science Ship seeds (Pictures + Seeds)

MORE NMS Ship Seeds - 362 DROPSHIP seeds. (Pictures + Seed)

EVEN MORE NMS Ship Seeds - 415 Shuttles (Pictures + Seeds)

423 FIGHTER SEEDS for NMS (Pictures + Seeds)

843 Multitool Seeds (Pictures + Seeds)

(browsing galleries by Reddit user Because_Bot_Fed)