Originally Posted by 13eastie
There is also the issue that block down-shifts e.g. 4-2 require both input shafts to be enaged since changes involving only a single shaft are not possible.
Anyway, to answer the OP's question, the 6MT is currently the only available option.
If you are decelerating on a track you could go 4->3->2 in which case the transmission computer would likely predict ("guess") your next move and each shift would each be preselected and quite quick. If you wanted a freeway cruising speed 4->2 direct it would probably be a bit slower but not terrible - worst case scenario somthing like a 4->3 in an SMG (or maybe a bit worse than that).