I'm trying to keep my reference image that I important as a plane in Material mode while I can still adjust the object I'm modeling by switching between Wireframe and Solid (by using Z). Every time I hit Z the reference image goes to wireframe/solid. How do I go about this? Google is yielding no results, or I just don't know the proper terms to use for searches. I am using Blender Cycles.
In the object properties there is an option called maximum draw type. Set this to wire. It will display the object as wire like the wire view mode, although a handful of things are different regarding selection in edit mode and such.
If you want to select the object like in wireframe mode as well, you can turn off limit selection to visible: