In this new video Billy from the Fuji Guys mentioned that a new Fujinon XF 50mm f/2 lens will be announced "later on" (check the 9:37 mark from the video above). The new 50mm lens, together with the Fujinon XF 23 and XF 35 f/2 lenses, will be part of the so called "designer series".
Update: that lens was already on Fuji's roadmap.
Via FujiAddict