Graphic Design for a T-shirt using sketches of vehicles included in image

I am looking for a design to go on T-shirts that includes the two vehicles as depicted only as graphic of sketched vehicles. In addition I want the wording to be placed in a size and font that is appropriate for the shirt and the design. The company I use has guidelines that define the acceptable formats the artwork has to be in. I'll send those requirements to the selected designer but it is the typical vector art, and resolution type requirements that is familiar to designers.