Haven't read to much into it, so pardon me if It's right out in the open. But has there been a date set for them to unveil it?
No official word on an exact date, but it will come during the upcoming spring. Typically teams that change/update their logo do so sometime in April, usually a week or two prior to the NFL Draft. When the Lions updated their logo in 2009 they released it a week before the draft, this way their new logo was on the jerseys they give their draft picks.
So while no official word, expect it in mid-late April.