Few months ago Samyang inquired about a potential tilt-shift lens on Facebook. A reader recently asked Rokinon about a possible tilt-shift lens and their response was "we are working on it":
Rokinon is a different marketing name for the same lenses that are currently sold under the Samyang brand. For example here is the Samyang 35mm f/1.4 lens compared to the Rokinon 35mm f/1.4 lens: