With the Canon RF 70-200mm f/2.8L IS already announced, it was only a matter of time before an f/4 version of the lens hit the market. This patent shows that Canon is actively working on such a lens.
Unlike the RF 70-200mm f/2.8L IS, the f/4 version in this patent appears to show an internal zoom lens design.
Canon RF 70-200mm f/4L:
Focal Length: 72.20mm 130.45mm 194.20mm
F-Number: 4.00 3.95 4.00
Angle of View: 16.68° 9.42° 6.36°
Image Height: 21.64mm 21.64mm 21.64mm
Total Lens Length: 215.54mm 215.54mm 215.54mm
BF: 25.98mm 25.98mm 25.98mm
Additionally, there is also an optical formula for an EF 58mm f/1.4 with what may feature a dual AF motor focus system according to Canon News.
Canon EF 58mm f/1.4
Focal Length 57.79mm
Angle of View 20.52°
Image Height 21.64mm
Total Lens Length 163.89mm