Great Idea, I had all the materials to fab up a bumper mounted spare (with idea's from DTB and 79coyote) until I lucked into a oem swing out spare for my 85 4Runner, complete with bracketry for the latch (inside rear quarters and tailgate).
However I'm not sure it will hold up to the weight of a 35" Truxus on 10"rim. Good Idea about approach angles, I'll take that into consideration.
DanS