I'm in no position to be making Bricklink orders for parts right now so I've been trying to use the alternative; my imagination. As it turns out it's a lot harder than it sounds for me.
*I trying to get some more shape out of that roof WITHOUT the use of slopes.
*I've tried and failed at a half dozen working door designs for that shuttle bay on the top.
*The engines are to big IMO
So have at her with the C&C y'all.

<(kidding) Keep up the good work, and I hope to see a finished product (eventually) !