oh man... it sounds like a hard work for me.... 20 gundams in 4special carriers... hahah i'l put the Eternal Class Carrier Ptolemaios Class Carrier, Futune Class Carrier and Galdia Class Carrier... how do i make a mod and does it need 3d designs?
Unless you're willing to play using the basic ship designs (which I bet you don't) ...yes you will need some sort of 3d model designer (easiest one being 3d Max if my memory serves me right) but the best (at least from my perspective (like I said earlier)) is ot download XSI mod tool 6.
And how do you make the mod...well you go into your entity files and play with the values, abilities, etc...and 'customize' your ships statistics, research requirements,etc... and overwrite the previous mesh for a ship with your new gundam mesh!
Hum..my thoughts are messed up...but I think you should get the general idea 
