Pick of the DaySoyuz Rocket
This is a great build. It uses very clever techniques to get the curves that are expressed in the shape of the actual rocket. On top of that, this is a critical element of international human based space endeavor as the Soyuz Rocket is how we get astronauts to the Space Station.
Make sure to check out Kei Kei's Lunokhod 1 project as well.
There is absolutely nothing wrong with producing new sets for BttF on Cuusoo, but keep in mind that these pursuits are no different from all the minecraft reproductions that populate Cuusoo.
If you do this, make it clear what makes your project different and worthy of support.
It is fine to promote a line concept but your actual product must be able to stand on its own as well.