Level editor?

Sorry if this question has been asked before but its essential information to what Im doing right now.
Basically what I want to know is can blender be used as a full scale level editor, like the ones that provide unlimited space for like Unreal, and racing games and stuff like that. Thing is I tested it by scaling a cube up to see how much space is there but eventually the sides of the cube reach a point where they disappear. So I’m assuming thats blenders level editing limit in terms of level space?
Just to point this out Im not using the blender game engine, Im using a C++ game engine but Im going to be exporting the geometry from blender.

But I really appreciate any help or advice anyone can give me on this subject. thanks a lot.

Blender’s editing space is limited only by 32bit floating point accuracy (assuming you have a 32 bit build), in the view properties there should be an option to increase the draw distance (also a view distance option available for the camera)

Regardless what engine you use, you should know that cameras (when using-z-buffer) always have a viewing distance. Together with the screen border it builds a viewing frustum (see wikipedia). Everything outside this frustum is not rendered. While you wouldn’t notice when outside the screen border, you can see it when a point is outside the near and far clipping distances.

This method is not limited to games. It is a common technique for any realtime 3D rendering incl. the Blender Editor.

As Ace Dragon already wrote, the geometry is there, just not visible. Move the camera and you will see it :).

When you export your models you can even look into the file checking that the data is there.