I think my ideal is Billings Estate Museum. According to Virtual Museum Canada,
"The Billings Estate Museum was the home and property of the Billings Family, one of Ottawa's founding families. Five succeeding generations inhabited the architecturally unique Billings house, Ottawa's oldest residence, from 1829 to 1975. Designated by the National Historic Sites and Monuments Board, the imposing house is the centrepiece of the Museum which also includes outbuildings, an historic cemetery, fragrant and colourful flower beds, heritage plantings and centuries-old pathways on a lush green site of 8.4 acres. Museum exhibits illustrate the intertwined stories of family and community life over 200 years and showcase the diverse collection of over 24,000 artifacts owned by the Billings Family. An extensive programme of special events, school programmes, adult learning workshops and lectures, and other activities animate this landmark of local history throughout the year."
I already found out that renting the property is only $150/hour and includes use of the grounds, the kitchen in the house (for the caterer), indoor bathrooms (no portable bathroom rentals), a white tent with a wood floor, and I can bring my own caterer and get my own alcohol. That's a deal!
I googled Billings Estate for pictures and found tons of images from people's weddings. Lots of couple chose the location just for their photos, but why not stay for the whole day?
I think it will be perfect for an outdoor reception, and this way if it rains we have our Plan B right there with the tent.
More details to follow!