This is a low poly delivery truck created for your mobile platform projects. The FBX model consists of 350 polygons (including wheels) and a 512x512 diffuse PSD texture. It's ultra efficient and lightweight. I have bundled a mobile reflection shader to help get a nice metallic look on the vehicle at a very low performance cost. You can find it here on my Unity shop: http://fatboxsoftware.com/unity-shop/4574957484/Delivery-Box-Truck/6467632 Link to a webplayer view: http://dl.dropboxusercontent.com/u/16956434/AssetStoreDemos/BoxTruckWebplayer/New%20Folder.html
Those wheels need more polys. No way around it. They kill the overall quality of the model. Further rigging it for rolling wheels would really suck for movement if you use the standard physics models. Those flat spots would just be a pita on movement. I would give up the shiny metal effect for smooth round wheels. Good attempt just needs some refinement.
I feel you on your concerns for sure. I made a decision based on some factors. The wheels are rarely seen in most driving scenarios so they got the least love in poly count. I found they really aren't seen at all. Secondly on most mobile devices it's not noticeable when they are seen, the vehicle is so small. Lastly it's important to note that the art wheels would never be used for physics calculations, so it plays no role...it's simply a visual.