An Amelanchier is an option, it has white flowers in the spring and red foliage in the autumn, or perhaps the flagpole cherry (Prunus Amanogawa).

Alternatively you might want to think about a shrub as some of these can grow up to 15 feet. A Philadelphus or Hoheria might suit.

A final suggestion is a fruit tree - by selecting the type of root stock that has been used you can limit the size of the tree.

As for the willow you might find the discussion on this forum of interest:

http://www.gardenlaw.co.uk/trees.html