In the 1987 New Brunswick general election, the Liberals won all 58 seats of their 58-seat provincial legislature. I am betting you wanted a more exciting example though...

In the first four consecutive general elections after Singapore's independence from Malaysia, in 1968, [1972] (http://en.wikipedia.org/wiki/Singaporean_general_election,_1972), 1976 and 1980, the People's Action Party won all seats in Parliament, winning 58, 65, 69 and 75 seats respectively, with walkovers in most constituencies.

It's worth noting that there was very little opposition (even less so than the others) in 1968 because almost all of the opposition parties were boycotting the elections, mainly due to disagreements involving Singapore's separation from Malaysia.