Olympus did it with their OMD line. The E-M5 had a huge success and they therefore expanded the OMD line at the top (E-M1) and the bottom (E-M10).
And if Fujirumors is telling us the truth than this could happen with the X-T1 line too. FR says a new entry level X-T1 will be announced within the next couple of months.
There is yet no specific info about the camera but I think it could become a hotseller if Fuji doesn’t strip to many X-T1 features from it!