No one can tell you the answer since no one knows.
Personal ship = personal roleplay = case by case basis.
I would hire a modeler to make one for me and try add it , but Never mind new version is never coming out anyway and if he does , pretty sure they will CBA to add it
No new ships are being accepted for 4.86, GMS ships aside.
If you want to have a personal ship, roleplay that you already have such a thing or are constructing it.
None of the current personal ships have been added and then involved in roleplay, other way around is the way to do it.
If it all works out well and folks think you ought to have it, your chances improve a good amount.
You do still have the hurdle of "Why?" to contend with though.