Official Mango 7720 release leaked on XDA
Yup, this story is still developing but it looks to be the case. A poster by the name of longshot442 has posted a 404MB file which contains the official RTM build of Mango aka build 7720.
Evidently, users are able to flash devices ranging from NoDo, 7661 or build 7712 up to 7720. You do not need to restore from your backup, but instead can update directly.
User cyberdel was one of the first to successfully flash once the file was uploaded:
"install on htc trophy is finished:
at first i see on the bootscreen there is no mark anymore like "Not for resale" an Version is.... tada.... 7.10.7720.68
i am very happy now, good night"
Others since have reported success as well, regardless of device, carrier or network i.e. this seems to be like the developer release, meaning device neutral. Instructions, translated from German, can be found here. You can download the files at your risk from here or here. Original thread at XDA begins here, which we strongly encourage you to read first! Alternative, simpler thread can be found here. Discuss in comments.
Remember, this is at your own risk! THIS MAY PREVENT FUTURE OS UPDATES FROM MICROSOFT. Make and save your backups. We do not endorse this method at all and take no responsibility. Having said that, enjoy. Thanks, William C., for the tip!
Image Credit: Lucas