The White Dove Tree, Davidia involucrata, might fit the bill - hardy in your zone, matures at about 50 feet, moderate growth rate. I'd love to have one, tried a couple of times but they just didn't make the winters here, despite the fact that I've seen them a few times at local nurseries.

Slower but a magnolia perhaps? If I was in the south east my yard would be full of live oaks and magnolias!

Full sun fast growing white flowers.... google cornus controversa and cornus controversa "june snow".

I have one of the regulars. Seems like it may want to get as wide as tall. Same with the one MOBOT has. Perhaps more height down south.

Horse Chestnut, Aesculus hippocastanum?

Thanks for the suggestions! After doing some looking online, I am seriously considering a Yoshino cherry tree or snowdrift crabapple. Any thoughts on these two?

At their best, the cherry and crabapple can be very nice. Problem is, they are rarely at their best. Pest & disease prone in my opinion. Also, neither will reach anywhere near 50'.

Dove tree!

Yoshino cherry can be very beautiful - it is my favorite ornamental cherry. Native choices might include 'Winter King' hawthorn or a type of Serviceberry ('Autumn Brilliance' is a good cultivar).