I think I'm following what you are asking. We have the 10 x something tiles in our master and we trimmed it out with the bullnose that matches the tile. I believe it's 12" long. I don't know if you can see in this photo, but DH staggered the seams so even the small pieces look OK. I can take a photo of the top of the shower wall. We didn't go all the way to the ceiling with it. If you want me to take a photo of that, I can post it tomorrow.

The bullnose on the front of the tub is a different stone than the tile and it also came in 12 or 13" pieces.

{{gwi:1387353}}

You can also do a chair rail, either wood, ceramic, or tumbled stone.

We're doing subway tile half walls with a chair rail above it. We are considering doing a border of Calacatta tiles above the subway tiles (5/8x5/8 square Calacatta) then the chair rail will be Calacatta as well.

thanks for the suggestions

brutuses, yours looks great but there are only a couple of tiles on each side. I don't think I would like to do that over a longer stretch of the wall.

Chair rail with a border under it would be great, the problem would be finding one that matches.
Redroze, what you are describing sounds beautiful, but we are using ceramic tile and most of them don't come with that many options, very few have a matching chair rail. I never thought of wood as a possibility. Now that Bill mentioned wood, I can think that a nice detailed one painted to match the tile, may be a good alternative.
Will definitely keep that in mind

We will be putting in an accent piece with pencil liner above and below the accent. The store you are buying tile from should have suggestions, if not a designer to help plan the design. Good luck!