Here's a list of potential builds I consider creating:
1. Evil Mansion / Plantation from Stay Alive
2. Area where accident happens in Half Life.
3. My version of what Area 51 looks like.
4. Inside of Senate Chamber from the Star Wars prequel movies!
5. A space cruiser
6. A Battlestar (maybe the Galactica!)
7. Jedi / Sith Temple
* I do not mind if other people make these builds too or already have done so.