maybe?: http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=c153

Ginkgos are magnificent trees, but they do get enormous--way larger than 40 ft and very broad as well.

True. Was ignoring height restriction.

Bruce, why do you have that height limit? Is it close to the house?

Any bigger than that would be higher maintenance and block the view. But trees usually don't get to their full height in our soil so it still may be a possibility.

If a 40' tree was near enough, you'd need a 5-story tower in order to see over it. I'm confuddled about where from the additional view a typical shade tree would block. The bulk of tree maintenance is removing lower limbs as they grow in order to maintain the view (and ground space) below them, so it would be similar for any size tree.