Irrlicht Engine

Is there a way to change the color when rendering as a wireframe? also is there a way to do wireframes without being able to see through the object as if you had a black model and just outlined the edges?

Change the node's material - the wireframe will use the same color (or texture) as the default rendering.

Second question: Depending on your model (won't work for hollow models containing holes etc.) the dimensions, etc.:
Render the node in black (non-wireframe), resize it a little bit increasing its size slightly and render it again (this time wireframe color + wireframe mode). Might also be enough changing line thickness ... just test it.

Guess it could be done using pixelshaders too (drawing pixels next to edges in a different color) - similar to cell shading with outlines but don't ask me how.