[Gargamel]

Sounds Like to me you don't want different ships per se, just more of them.

First off, if you are really looking for the more arcade style of play, try Jim's spy sat mod, it gives you a gods eye. Jew of the world, allowing your to home in I targets quicker.

Also, I think your best bet would be to just edit the campaign files, back up the originals first. There are many other threads in the mods forums about using the editor, I'd check there. You would be able to greatly Increase the frequency of traffic, giving you more targets.