[TML] Firefly, wait no it is a Subsidized Merchant ship.

[Tom B]

>  The real bulk goods freighters would also have bottom hatches for a gravity
>  assisted unloading.  (Of course any ship with contra-grav could just hover
>  upside down.)

Sure. Why not have the whole cargo bay floor lower? Or land the ship,
run down the landing jacks, disengage the floor release, jack the ship
back up on the landing jacks - cargo delivered.

I'm not sure the contra gav idea is wise. For many cargos, you'd want
to harmonize ship grav with planetary grav to avoid destabilization.
In your case, you're talkng about lifting things out the ceiling
against the pull of grav plates and then having it take a 2G change to
being pulled towards the real ground when you exit the field. Not so
good for live cargo or wines or... well, you name it.

>  Most likely, starports will be of all types, matching the local conditions
>  and capabilities.  Merchant ships that want to use all of the ports would
>  have to be able to land at any of them.

This justifies a very large number of variants of standard imperial
designs - some tailored to water landings, some to mult-environment,
some to wilds landings, etc. It justifies the odd variety of ship
shapes you see in ports too.