Stuff I felt should exist....

[swordtart]

There are ways and means under the existing rules:
Minivan trailer with explosive hitch.
Flatbed (or 10 wheeler with assault ramp) with a subcompact kamibomb (with no plant needed) rolled off the back.

But, personally, if you want to mount a bomb in your car to roll out of a bomb bay like an aircraft, I am not sure I'd have a problem with it.

You would need lots of ground clearance to under mount it though*
You would need something like a cargo door and whilst it was open you would have no armour on that side (it could be rolled out the back or either side) and you would need to mount a winch to push it out as a firing action (or have some passengers to roll it out manually).
Alternatively mount it in a Rocket EWP with explosive bolts.

You would need some sort of remote detonation mechanism (radio probably) as you wouldn't be able to use any sort of impact detonator.

Unlike a mine it would have enough mass to inherit the velocity of the vehicle that was dropping it.
When it hits the ground treat it as a semi trailer with an emergency plate (i.e. HC -6 while moving, using Crash Table 2 as necessary; it cannot manoeuvre, and decelerates (without hazard) by 30 mph each turn).

So basically.
Turn 1 open door and lose armour protection.
Turn 2 deploy the bomb and have it potentially slide off in a random direction.
Turn 3 you can recover your armour.
Turn 3+ you can use a firing action to detonate it.

If you were willing to accept all that then go for it.

*I'd say allow 1/10 of the body spaces rounded down available for under mounted drop bombs. If you have OR suspension you can round up. These could be flatter in profile than an air dropped bombs.