You might be interested in this recent article in the JAH:

Wigmore, G. “Before the Railroad: From Slavery to Freedom in the Canadian-American Borderland.” Journal of American History 98, no. 2 (September 7, 2011): 437–454.

It's a regional study of border-making in the Detroit area during the late 18th and early 19th centuries, and doesn't quite address your question -- there's not enough of a national focus to offer a picture of how this case fits into broader efforts to have Canadian authorities extradite U.S. slaves. But it does give some useful context on the nature of the U.S.-(proto-)Canadian border at the time, and shows how difficult it would be have been to enforce extradition.

Not Canada but in another British controlled territory in the West Indies, something similar happened. The slaver Creole was engaging in the interstate American slave trade, when some of the slaves revolted and sailed into a British port. Secretary of State Daniel Webster employed numerous arguments for financial compensation for the slaves(none of which relied on the Fugitive Slave Act) and despite close relations between the Tories and Whigs no compensation was quick in coming. Negotiations continued on and off into the next decade before Britain finally approved compensation.

Canada wasn't allowed to make its own foreign policy until 1931. So it wasn't an issue. The UK wasn't about to bow to American pressure on slavery.