The-Digital-Picture has written a cool little article about the 10 oldest Canon lenses currently in production.
- Canon EF 50mm f/2.5 Macro Lens Buy – 1987
- Canon EF 50mm f/1.8 II Lens Buy – 1990
- Canon EF 100mm f/2 USM Lens Buy – 1991
- Canon TS-E 45mm f/2.8 Tilt-Shift Lens Buy – 1991
- Canon TS-E 90mm f/2.8 Tilt-Shift Lens Buy – 1991
- Canon EF 85mm f/1.8 USM Lens Buy – 1992
- Canon EF 20mm f/2.8 USM Lens Buy – 1992
- Canon EF 400mm f/5.6 L USM Lens Buy – 1993
- Canon EF 50mm f/1.4 USM Lens Buy – 1993
- Canon EF 70-200mm f/2.8 L USM Lens – 1995
We've been hearing for a long time that the tilt-shift lenses would get the L treatment and that the 50 f/1.4 would be replaced with a slower IS version. All of which are expected in 2014.
The 400 f/5.6L has been often rumored for a replacement. We recently heard about stock issues with the lens, and the possibility of an IS version arriving for Photokina in 2014.
I wouldn't expect a replacement for anything else on the list.