I'd be careful, too, but in both directions, and it all depends on how the NDP "establishes" itself over the next few years--in the end, any breakthrough here might have less to do with the now-decimated 70s-style "working class" than with a little Millerite Parkdale-High Park yupscale energy spilling over the Humber. Or other factors--after all, a "validated" NDP could, with the right candidates and campaigns, wind up making critical breakthroughs in parts of Brampton/Mississauga that aren't Bramalea-Gore-Malton. Remember that there may be a pool of "latent/potential" 905ish NDP support that was still suppressed this past election, due to uncertainty about an untested brand and untested local candidates and maybe residual memories of 1990...
How about David Miller as the federal NDP candidate in Etobicoke-Lakeshore?