The first attempt was by Marianne, designing a napkin ring using the TinkerCAD (www.tinkercad.com
Unfortunately this didn't work:
1. At the time, something about it (the complexity) meant TinkerCAD couldn't 'join' it, so instead of the STL file (that you need to print an object from) being one solid object, it was an object per letter that overlapped - which seems fine but really causes issues with 'Slicing' software. It seems TinkerCad have now fixed that though, so potentially they are an option if you want to do something like this.
2. If you think of the object sliced from bottom to top as the printer prints it, there are lots of separate pieces and in some places there are pieces that have nothing to be printed on top of (for instance if the middle of the 'M' doesn't touch the bottom). Some 3D printer software can insert 'supports' to get around this, but they take time to pull out, and even more time to print!
Also, it would have taken ages to design each napkin ring individually...