Simple line drawings do not take the artist as long to do compared to vector conversion with color and gradients. They are also done for less money for this reason. You can see how a line drawing of a truck would look below:
If you have something as detailed that you would like a vector line drawing of, you can get a quote here: HERE. (No account necessary)
Please make sure to state that you only need a line drawing when uploading your order/quote request.