Spiky plants for a large trough pot

I'm planning on purchasing a modern 100cm trough planter and am looking for options on good architectural plants. I love cordyline esq. (esp colour of red star) but I believe these grow to over a meter tall. ideally the max I need the plants to grow through to would be 50cm as the planter is 45cm high and is to sit in front of a window and i dont want to fully obscure the view! Not keep on whispy grasses … was looking for something with structure but with some colour to the leaves. Any recommendations?