Clear Plastic Frames from Walmart are cheap, and you can decorate them with paint pens, if not with the girls names, then with DZ letters.
Its easy to decorate a glass mason jar with ribbon (just use got glue) and cut out letters (I use my Cricut Chirp machine). You can then cut fortune cookie sized papers and print DZ and sisterly quotes on the papers.
Theres alot of cute ideas for crafts on this website...
http://www.scrapjazz.com
just check out the gallery!
good luck