On the topic of a drop down tail gate, could you pilfer the hinges, and the gate latch from a chev truck, the one that my father owns looks like it could be modifed to do the trick. as far as the spare tire you could fab something similar to a jimmy spare swing arm that bolts right above the tail gate to the spot where the body panel spacer is removed for the european roof rails. Of course you'd have to use bigger bolts then the spots provided. It might work, just my two cents.