There should be certain units which can funtion as transports - eg. Trojan Horse(?), Certain Ships, APCs, Bombers, other large planes, missile submarines, trucks...

And certain units that can be loaded onto these transports and deployed elsewhere...
For example, a SLBM (submarine launched ballistic missile) would have to be loaded onto a sub and taken within range of the target.. Paratroopers could load and unload from large planes.. Nuclear bombs from bombers etc..
And trucks could be used for land transport of items, which I have so far not thought about (like nuclear devices - see Improved Nukes) etc.

according to civ2 models it should be:
a/d/m: 0/4/7. That way you can pillage your enemie's infrastructure while having tools to cope with it. Also it is annoying when I conquer civs that discovered rail road 2 years ago and haven't put it to a good use.

Each truck can do only one of the following in a given time:

- can carry one nuclear bomb
their functionaltity is like a spy planted bomb, but they're used in times of war and have not penalties and high success rates. The nuclear bomb it self will cost big money. The truck is destroyed on detonation (well duh!)

- can carry up to X (5 or so?) land units (only foot soldiers.)

- can carry ICBMs (so you can transfer them to cuba )

- maybe there should be a "super truck" which can transfer 1 or 2 land units like tanks and artillery. There are such things in reality. Also if you check out old films, about war n'stuff, you can see that many vehicals have medium sized artillery units attached to their back side. It's like when you use one car to pull another from deep mud or something. I also depends on tank size and truck size. but if you limit it to game size, 1 truck can carry 1 or 2 tanks (on the truck) + 1 artillery (attached).

I have been waiting for something like this. I just hope I won't be disappointed if I own't like it when I get it. :x