This is an experiment - I have permission to release one or two DNG files - of course, they are fundamentally hamstrung by being my photographs, but I can't do anything about that!
There is also a potential problem with dropbox limits - I do pay for it, so there is a larger daily limit, but please don't download the file over and over again.
If this is a success, then I'll be able to make other files available. I'm doing it through my website so that my son can amuse himself with the metrics!
You can play with the file, and then you can post your conversion on this thread.
Click on the Downloads link on the top right
This is my take - I'm sure you can do better, my lightroom skills are still light!.