2.5: Toggle in wireframe/solid mode only selected objects

Hi all,
as everyone of you knows, the Z key put all the scene meshes in wireframe/shaded mode.
I’d like to create a little plugin in Python that works in the same manner but only with the selected objects, I suppose, it toogles Display->Type:Wire/Solid, then later I’d likl to associate this plugin to SHIFT+Z.

This is useful when you model something like an head using an image plane as reference and you have to switch from wireframe mode to check if everything respect the concept to solid mode to check the appeal of the model: using the buttons aren’t a speed way and they break the concentration and artistic flow.
Please, if someone has tips to share or this plugin exists, please let me know.
I have to work to a project soon and I have to program this in very few time.
Thanks in advance.