I don't know what it's like where you live, but mid-century architecture is rare in these parts which makes search for appropriate pieces like a treasure hunt. Here's the results of my web research.
Top Left: Neutra House Numbers in Aluminum from Design Within Reach $24.00 USD each.
Top Centre: Sausalito House Numbers in Zinc from Chiasso $14.00 USD. Also available in Espresso
Top Right: Parragon Modern House Numbers from Atlas Housewares $25.84 USD. 4" Stainless Steel on Black Poly Fibre backing.
Middle Left: Modern LED House Number by Luxello from Surrounding Modern Lighting & Interiors $57.00 each
Middle Right: 4" Modern Font from Modern Dwell Numbers $21.99 USD each. Also available in Black and Bronze for $28.99 USD each.
Bottom Row: All from West On Letters
Left: 3" Ribbon Black Annodized Finish
Centre: 4" Ribbon Condensed Natural Satin Aluminum
Right: 5" Ribbon Deep Natural Satin Aluminum
I knew what I wanted and was I ever surprised to find them at my local Lowe's for $7.97 CAD each. They are 5" Black Ribbon Elevated Mount numbers.
Click here to see how they look on our house.