You know what I don't get.
I remember seeing a white paper from GM a few years back maybe 04 or 05 bragging about building a manual trans that used planetary gears and that even though it was more expensive it allowed a stronger more compact design.
Ours doesn't does it. So what happened to that design?
Maybe it's just me but the bulk of O.E.M.s seem to save the latest and greatest until a generation before (4-6 years) their competitors come out with something on similar footing. This trend appears to be supported by body styles, trans selection (DCT), engine control (Cyl shut down), fuel economy (mostly gov't pressure), and other such factors. Of course there's a few exceptions which seemingly go undocumented to the general public (lithium Ion batteries for the 90's EV-1 all electric GM car, BMW's Valvetronic, etc)
Now as to a planetary manual my dad's 1980 John Deere 4850 has a 15 speed and 4 reverse manual trans........ Clutch and all. I think it's around 200hp and god knows how much torque (apparently HP numbers are more important in a tractor the TQ

).
It's really cool because after putting it in gear ( be it 1st or 6th) you can shift WOT, under load, and no clutch and it's much like a sequential, just push the lever forward a notch for the next gear.
Then again some things fail to reach production because of cost, quality concerns, inability to mass produce, or maybe it just really sucked after being tested.