looks good to me. id probably prefer it with tonneau cover. im sure the topper will look fine, but im not sure how the 'walkthrough' is gonna work. are you going to connect the topper to the cabin portion so it looks like one piece? i would hope any vibrations or body flex wont crack the seal between the two.
It will crack, some people use a flexible acordian-like rubber "gasket" between the cab and topper. Good call though.