These might "sound" cooler, but what about adding a BTC symbol instead of anything random.
Legendary BTC or BTC Legendary
While I remain opposed to another rank, I would argue (if there really is a new rank) for a clearly visible difference from Legendary status. Like for example:
Epic
Elite
Veteran
I think BTC Legendary looks more unique and defines what you are called a Legendary in this forum. Whether or not any changes happen with the Rank system but if it happens and there is voting I would support it. Epic, Elite, and Veteran are some titles that have been used or are being used in other forums. Creating something unique like this one gives a unique identity to those who have achieved it.