Not sure about the Conv Jimny only being built at the Santana factory. At least it wasn't being built there when I lived in Germany around 2000. From what the German dealer told me, the Santana factory only built the Samurai and, from what I've read later, had lots of quality issues, so Suzuki pulled their support/product from that factory. I'm sure there were some political and economic factors as well.
AFAIK, the convertable Jimny has died off due to lack of consumer demand. People want more refinement, quieter rides (so they can talk on the phones/hands free systems, cool in the summer/hot in the winter (better than what a single ply top can provide).
As far as the X-Head, I don't think a cab over would pass most safety (crash) tests. VW recently tried to bring back the microbus and they couldn't get it to pass safety tests, even with the front bulging out a bit, so they killed that project. I still think an updated LWB Samurai with a larger 4-cylinder, coil suspension, safety items, would be a hit. Think of a 3/4 size Land Rover Defender.