I think a good option for Topp could be Hull-Aylmer. Nycole Turmel has capped off a stellar career with a stint as Opposition leader, but any shadow cabinet position after her current one will be a step down. She'll be 72 by the time of the next election, so even if the NDP became the government she may be too old for a cabinet position. I could see her stepping aside sooner, for the good of the party, if the new leader needs a seat.
Very logical, but raises a question for Pierre Ducasse and his fans. He was going to run again in Hull-Aylmer until he stepped aside for Nycole Turmel. Assuming she does not run again in 2015, Pierre would be a logical candidate. If Topp took Hull-Aylmer in a by-election, would he move elsewhere in 2015? Not necessarily.