Sorry about that, I did misunderstand what you were getting at. I didn't know interior linemen couldn't declare. That is why I love this site... you learn something new everyday!
Thanks.
An example of this in the college game can be found in the 2005 Ohio State - Michigan game.
Ohio State wanted to grind the ball at Michigan so they were using one of the backup OTs as a TE although his number was 79.
You'll hear it called an "Unbalanced Line" and it's in use in a LOT of High Schools that have more good linemen than positions.