OK, we have never done a Jesse Tree and I am not sure that this will become a family tradition, but it is something that I have wanted to try. With a 7 year old and a 4 year old, there is no time like the present.
I originally read about the Jesse Tree last year over at Rocks in My Dryer, but did not have the time nor the peace of mind to create it. We have more time this year and I have already gotten started.
Here are some of the links that we have used, as well as, the Bible. My kids are half listening but are enjoying creating the tree.
The Story - http://www.cresourcei.org/jesse.html
Scripture - http://www.shalfleet.net/advent/makeajessetree.htm (look towards the bottom).
Ornaments - http://www.eriercd.org/jessetree.htm , http://cnsblog.wordpress.com/2007/12/19/jesse-tree-ornaments-available-for-download/ This site has a link to two different size ornaments. I liked these because they looked the same and not to ornate. Hopefully one of these links will work for you. I could not open it with the first link, but used the second link just fine.
Hope this helps you feel that the Jesse Tree is doable for your family as well. You might learn something new from the Bible in the process.
Have a great day!