It looks as if you have plenty of shade so are you just looking for a screen? A good redbud would do that for you, one that has horizontal branching. A shade tree will get too tall and will give you no privacy. Gingko is too narrow. What about a Sorbus/ash or a honey locust?

Here is a link that might be useful: Propagating Perennials

We have shade at the rear of the yard, but none on the house itself. That photo was taken facing west, and it must have been relatively early in the morning while the sun was on the other side of the house. The driveway side and rear of the house gets blasted with sun later in the day.

The local nursery estimate for the ginkgo biloba 'Autumn Gold' (the only ginkgo they sell) is 65h x 45w in our area.

Honey locust is second on my list. It's probably most appropriate (size, filtered light so I can still have some plants), but in my head it has an unforunate association with mall parking lots.

I will look into ash.

Except Ash trees are being struck down by the Emerald Ash Borer, an imported pest that will probably exterminate all ash trees on this continent in much the same way DED wiped out the Elms, Chestnut Blight killed off the Chestnuts, etc.

Now, admittedly Maine is cold and the Borer may not be there - yet. But it is living in the upper Midwest, which is also cold, so who knows...