All full frame pro lenses:
16-35mm f/2.8 IS - Based on the specs this should be even sharper than the existing 16-35mm f/2.8, but much more expensive.
http://nikonrumors.com/2013/01/09/nikon-patents-for-16-35mm-f2-8-vr-lens-dual-lens-hood.aspx/
135mm 1.8 IS - This lens would not be especially hard to manufacture and is in bad need of an update.
http://nikonrumors.com/2012/03/09/nikon-135mm-f1-8-lens-patent.aspx/
55-300mm f/2.8-f/4.0 IS - This particular way of making this lens has f/2.8 until 140mm!!, doubles as a 77-420mm f/4.0-f/5.6 with a 1.4 TC - 5 ED elements!!! If it were good it would be very exciting.
http://nikonrumors.com/2012/11/13/nikon-patent-for-a-55-300mm-f2-8-4-full-frame-lens.aspx/
50mm 1.2 which isn't soft like the current Canon version:
http://nikonrumors.com/2010/02/07/there-is-a-patent-for-a-new-nikon-af-s-nikkor-50mm-f1-2g-lens.aspx/
Yes I know these are all from Nikon Rumors, but I hope Canon is watching them and responds.
These would be profoundly amazing
16-35mm f/2.8 IS - Based on the specs this should be even sharper than the existing 16-35mm f/2.8, but much more expensive.
http://nikonrumors.com/2013/01/09/nikon-patents-for-16-35mm-f2-8-vr-lens-dual-lens-hood.aspx/
135mm 1.8 IS - This lens would not be especially hard to manufacture and is in bad need of an update.
http://nikonrumors.com/2012/03/09/nikon-135mm-f1-8-lens-patent.aspx/
55-300mm f/2.8-f/4.0 IS - This particular way of making this lens has f/2.8 until 140mm!!, doubles as a 77-420mm f/4.0-f/5.6 with a 1.4 TC - 5 ED elements!!! If it were good it would be very exciting.
http://nikonrumors.com/2012/11/13/nikon-patent-for-a-55-300mm-f2-8-4-full-frame-lens.aspx/
50mm 1.2 which isn't soft like the current Canon version:
http://nikonrumors.com/2010/02/07/there-is-a-patent-for-a-new-nikon-af-s-nikkor-50mm-f1-2g-lens.aspx/
Yes I know these are all from Nikon Rumors, but I hope Canon is watching them and responds.
These would be profoundly amazing