417: Ottawa: Expansion to a consistent 8-lane cross section from Kanata to the Split (Ottawa Road 174) is about the best that can be done at a reasonable cost (limited right-of-way)
Already happening. The bridges that were recently replaced at Island Park Dr, Carling Ave, and Clyde Ave are spans that can accomodate 4 lanes instead of 3. (Side note: for anyone who hasn't seen the replacements, it's quite an engineering feat. The bridges were all replaced in about 17 hours. The spans were built adjacent to the highway, and then over the course of 1 weekend the highway was shut down, the old spans were wheeled out, and the new spans were wheeled in. The timelapse video of it is pretty impressive.)
The 417 between Nicholas St and the Split is also to be widened, open in 2015. This was accelerated because the lanes will initially be used as HOV lanes/buses only lanes while the Transitway is shut down for the upgrade to LRT.