definitely making these! How about adding a string of white or clear christmas lights to them. You can get them so cheaply with green wires but they can be covered with white tape or spray painted white or even left green. I think the different size "globes" would be awesome when lit up!
Yarn around balloons Elmers glue! Could make these with a small opening in the top, and use as "vases" for the centerpieces, filled with a few fake flowers! Quick, inexpensive and easy!! Could even do this as a craft with the mommies.