I'm 5'4" and all of my Burberry trenches are mid length and I find this to be the perfect length for me. Like you, for my first trench, I wanted it to be a classic, so I just listed off the characteristics I was looking for to my SA (honey or trench colour, cotton gabardine fabric, and check lining and undercollar) and she brought me all the options that fit what I was looking for. I have also ordered off the Burberry website and the nice thing about that is they have a live chat feature that allows you to ask as many questions as you want and you get answers instantly, so this might be a useful tool in your research! My tip if you do end up ordering off the Burberry website would be to remember that they list everything in UK sizing, so if you are not in the UK you will have to convert to your normal size. I hope this was helpful!