As for how to make the design, you can do it yourself with free online software. I used 123D Design to make this one. Here's how.
Step 1: Start With a Circle
This is a really short tube. 35mm wide, 3mm tall, and 3mm thick.
Step 2: Copy the Circle
Make a copy of the circle and move it away from the first one. Group them together and you have your first pair.
Step 3: Copy the Pair
Copy the pair of circles and rotate the copy 60 degrees.
Step 4: Third Pair
Now make another copy and rotate it 120 degrees.
Step 5: Align!
Use the align tool to center all the groups in both the x and y directions. Now group them all together.
Step 6: Shrinking, Pt 1
Make a copy of this group and shrink it down
Step 7: Shrinking, Pt 2
Now make another copy of the group and shrink it down even more. Here the three groups have been changed in color to see where they are more easily.
Step 8: Make the Loop
Now the the design is done we just need a place for the thread to attach to. So make another tube that is 9 mm wide, 3 mm tall and whose walls are 2 mm thick.
Step 9: Place the Loop
Move the loop into place.
Step 10: Align Again
Now align the loop with the rest of the design to center it.
And you're done! The design is ready to be exported for a print.
Step 11: Print!
Now print up the ornament! You can use a home printer like the MakerBot, but some of the details might get lost. For better detail a print with an online service in nylon will get cleaner results.