Yes, planned late-game storyline missions do involve an attack on the Taman homeworld and the alien mothership. I like the New Praetorian the best. If you get the texture finished, please share and we'll toss it into our data_source.
The third dropship you posted is my favorite. Not sure how we'd use it, but again, if you get the texture finished, please share it.
(btw - are you familiar with opengameart.org? You might think about throwing some of your work up there.)