The ship style templates are really for the AI. You can build whatever ships you want to - it's the AI that needs specific hull designs set out for it.

As for changing the starting ships, that takes an extensive bit of modding. I'm going to have to go find a post about it, as I don't know how to do it myself.

The survey ship, miner, and colony ships are in there:

All you need to do is pick from one of the available templates on the right, click Change, and then click Save Ship Style when you're done making changes.  The new design for your survey ship will take effect when you start a new game using this ship style.  Obviously it will just have the same functional components as any other survey ship, but you can use any cool-looking functional components you like in the template design.

Oddly enough you can't edit ship style for the race you have picked to play, just opponents.  Though obviously once you're done editing your 'opponent' you can switch things back around.