David Bertschi has set up what essentially amounts to an "exploratory committee" (or at least the front page of the website for one) in order to determine whether or not he should run for the upcoming Liberal leadership race, sometime either this year or early next year.
I actually had the pleasure of meeting Bertschi's wife briefly during the Ottawa convention, while in the line-up for the Subway in the food court. Very pleasant woman. Other than that, I don't know much about David, outside of his LinkedIn profile which notes he's a successful lawyer from Ottawa; and that Bertschi ran in Ottawa-Orléans in 2011, failing to win the seat but didn't drop the Liberal vote very far (though technically earned more votes because of increased turnout).
I'm not sure how many people would go to the expense of setting up an exploratory committee for the third party's leadership race, so I'm going to assume David is serious about this. If he is, then he'll be the second "confirmed" candidate for the leadership race, the first of course being 32-year old Winnipeger Shane Geschiere.
So still, we're not seeing any of the current caucus or former party bigwigs make any serious moves towards running yet, outside of the machinations of Bob Rae. I assume by June, when the race dates are finalized and the party makes it clear whether or not Rae can run for the permanent leadership, this will change (at least I hope so).