You can give army any number of movment points, and while without units it will use them. But if you put into army units with non zero movment points, army speed set to minimal speed of units(if army dont treet all terrain as road). However there is an expeption. If you put immobile unit into army army speed remain the same. IT mean that army could be used as moving platform for SMAC-type of unit. Have several kindes of armies with differend bombard, radar, speed, airdrop etc, upgradeble to each others and several building blocks, immobile with attak/defence. After that you can constract new units from that block. To make it easy for AI you can give this "platform army" carry tactical missile flag, and all block should be tactikal missile. That should prevent AI from putting wrong units into platform.
