We have Rose of Sharon growing along or 6 ft fence. It is dense and adds great privancy. The flowers and leaves are edible which the links below will tell you...we have not tried them yet. (We enjoy the blooms too much to eat them)
They grow in USDA zone 5 to 8.

This site says the flowers only last one day...we have the white flower and the pink flower and they stay from july through september and beyond.
http://www.gardensablaze.com/Shrubs/ShrubsRoseOfSharon.htm

http://www.google.com/images?um=1&hl=en&tbs=isch%3A1&sa=1&q=rose+of+sharon+hedge+pictures&aq=f&aqi=&aql=&oq=&gs_rfai=

http://www.ehow.com/how_4450900_grow-rose-sharon-hibiscus.html

http://www.onlineathens.com/stories/072510/liv_682592937.shtml

You could plant Filberts and instead of training them into a tree form, just let them grow in the form they prefer...A bush! I doubt they would get over 6-8 ft tall. You could plant Seaberries, they get to be around 6-12 ft depending on variety, Elderberries grow to about 6-8 ft, just space em at 6 ft apart, or you plant plum trees close for a hedge...my neighbor did that and the only problem with that is, the amount of fruit suffers, but if you have a lot of trees it all works out.

I would use the blueberries, but maybe a different type. Elliot blueberries get tall, but I don't know what would grow best in your zone.

Blueberries are easy to grow, especially if fruit production is your second concern. If you're looking for nice shrubs, attractive year round and great for the birds...blueberries would be great. Plus, what the birds don't eat, you can eat :)

What kind of soil do you have and do you know the pH? Blueberries need acid soil and need close attention to watering until established.

tj

You could always try a multi-fruit hedge as Toby Hemenway describes in "Gaia's Garden." He planted bush cherries, Manchurian apricots, currants, gooseberries, and many others. On the outside he left the wild fruit for wildlife, but he grafted domestic cultivars to the inside for him to eat. That way, you don't lose all your fruit if a disease strikes one kind. You'll always have something else for backup.