This is the end result...
This is what led me to making my own...
The above design exhibits a typical problem I have found with many designs in the 3D printing community (including some of mine). That is, they try to solve the problem using a single piece model. This leads to spider webs, weak joints and something you need to spend a long time cleaning up after printing. In fact I printed two copies of the failed design and while taking the second one off the printer bed I managed to snap it. I can't imagine something like that lasting any decent amount of time while in use. The second version even had retraction enabled, yet the spider webs were still there!
So I launched OpenSCAD and quickly put my design together...
Three pieces, all of which are more or less flat. All you do is print each piece and epoxy them together. It's stronger this way, there are no spiderwebs and I think it actually looks nicer too. I made the gaps in the base smaller than the sides on purpose - for wiggle room and for the epoxy to fit.
These are the pieces after printing, and then again after some minor clean up.
Once all the pieces were cleaned up using some small files, I did a dry fit along with the 15mm diameter rod I cut to size.
After applying 5 minute epoxy into the gaps in the base and putting the sides in and letting it set, I flipped the stand on its side and put some rubber feet on so that it wouldn't slip all over my desk.
With the feet in place it was all done and looked much better than the first model I tried to print!
The only thing I'd do differently if I had to make this again is either add more epoxy to the base or make the sides slightly thicker. This isn't necessary, but would look better in my opinion.
All of the files for this design are available over at Multi-Piece Solder Spool Holder - Thingiverse.