I am doing my PhD in the Southern Hemisphere, but last year I made contact with one of the top academics in my field on the other side of the world to tell her about my work, and say how much her research had inspired me. I felt like such a brown noser at the time, but I just really wanted to make contact with her because our work is very similar, just within different legal frameworks. Anyway, she responded, we kept in contact and now I am about to have a book chapter published in a book she is editing. This would not have happened had I not sent the email, she wouldn't have known I existed.
I'm sure not all senior academics are this friendly (well I know from experience they are sometimes not!), but it is definitely worth making contact to test the water. Just send an email explaining what you are doing. I'm sure if you say something subtly kiss arsey about their work too it won't go a miss. Even senior academics can feel inadequate and appreciate a bit of flattery.
Good luck!