This ship should be bigger because now its size is comarable to fighter but it is easy to change so I will do this soon
I don't know what kind of method use brand-x but I do this in 6 steps:
1. modeling ship
2. unwrapped it
3. render to texture only diffuse map
3. adding some details on texture in gimp or photoshop
4. apply this texture to model
5. add lights
6. again render to texture with baked shadows.
sometimes I use AO also baked on texture and use it as kind of dirt map
Galemp: 2048 isn't too big in my opinion because this ship has about 150m so it's so much bigger than for example Tie/In which has about 8m.. I don't think that brand-x will use texture for Tie lower than 1024
when I finish this ship I will send it to You so when You think that 2048 is too big You may easy change it to 1024
BTW. I use only one texture of course and maybe I add another one normal texture.