I love these puppies. I miss the old Alsatian brasserie nest to The Rose Bowl which served a good rendition. Le Manoir on Sources serves these, but only on Saturdays (I think). The rest of the week, they have a mix of meatballs, pork hock, sausages, and potatoes (quite good, actually). Of course there's Pied de Cochon and the Dominion Pub (near the Sunlife building) which has a neon sign advertising Pigs Knuckles, but last time I was there, they told me "we don't have any tonight..."
I also like them at Mazourka on Prince Arthur and to a lesser extent, Stash Cafe in Old Montreal.
Other suggestions? Maybe a corner tavern (uhhh brasserie) you know?
Also, are these a Montreal specialty? Seems like they don't have pig knuckles much anyplace else.