Crab Apple 'Evereste'. Its fruits stay on all through the winter and its a really beautiful tree. Check the ultimate size as I'm not sure how big you want to go. Or how about Cornus kousa chinensis..the flowering Dogwood with salmon pink bracts that stay on for ages. Then theres the autumn flowering cherry, Prunus subhirtella autumnalis which has gorgeous blossom during mild winter spells and on in to the middle of spring. It had lovely autumn colour and a nice habit. Or if you want evergreen foliage, how about Argyrocistus battandieri (The Pineapple Broom) which keeps its leaves through the winter except in very cold situations where it will be semi-evergreen. The yellow panicles of flowers in summer are scented like pineapple. One of my favourite small trees is Cornus Mas which has acid yellow flowers in late winter and deep red fruits which are popular with birds. :)

What about a nice acer :)

Cornus florida 'Cherokee Chief

Only grows to 30 feet, big pink flowers emerge in spring on bare wood before the leaves open, pyramidal shape, leaves turn red & purple in Autumn, red berries in autumn & winter, tolerates clay soils, full sun/part shade.

How about a holly ,Madame Briot would be ideal and easily clipped once it get to the height you want.

Bonus looks good all year

You could also go for dwarf eating apple. That way you get food as well.