Michael are you going back in with a tub/shower combo or just a shower?

Hello, I'm going back in with a stand alone shower, tile up to the ceiling throughout the interior of the shower space.

I'm using the Schluter Systems products for water-proofing and the KERDI-LINE linear drain assembly so, overall it will have a 'fairly modern' feel but I'm having a hard time finding design examples of what this 'could' look like.

What I'm seeing so far is a continuation of the Ogee across the curb threshold into the shower. Everything else just comes to an abrupt stop at the edge of the tile.

There are lots of options for transitioning your wainscot depending on the style. From your description, it sounds like the chair rail is your big worry. Are you using a traditional chair rail molding or are you using that term to describe the top of your wainscot design? If you post a photo of the style you are considering and the tile you have chosen that would help.

The simplest transition is likely to just return the molding on itself. This might seem like a shortcut but it simply allows for the molding to stop and the tile to start. Another option would be to create a 1-3" return on either side of the shower that matches the width of your curb and that you can tile with the same tile as the rest of the shower or a complementary tile. This would create a low profile "frame" for the shower and will give you something to terminate your molding into and a clear transition into the shower.

If neither of these options sound like they will work for you then post photos of your materials so we can get a better grasp on the overall look you are going for.