It can be done with success. I think it just needs to have a pleasing composition with whatever else is in the space.

No need to crowd the space. The the 60" will look great with the mirror.

Can the mirror be rotated to vertical?

About 90% of the time you will want your console longer than your mirror. The photo to the right takes a great design eye to pull off the look. You will notice the mirror becomes a piece of art onto itself, the legs of the console splay out to create a larger look, the ball is of a size that creates color interest and reinforcement of the very wide mirror. Additionally, the texture of the chairs anchoring the piece is a good solution to much needed texture, and again the tootsie roll pillow reiterates the black ensemble. This is not something that can be achieved by an amateur. The photo on the left is a good attempt by placing the table to the left and the bench to the left of that to visually anchor the overhang of the mirror on the right side. Sadly, it just doesn't cut the mustard for me. It's OK but there is nothing to make my eye stop measuring the distance between each side and I'm not seeing something in this scenario that makes me stop, stare and smile.

Either rotate the mirror as dclostboy suggested or go with the 76" table. If the 70" mirror doesn't overwhelm the space, the 76" table shouldn't either.

The mirror can't be rotated. There is a slight bump out that won't allow it.

Based on the picture would a larger table be recommended?