At 15 stone I wouldn't be looking at any bikes with a leverage ratio over 2.5:1 personally…
I'm 12 and a bit stone, and my Giant Reign X with 6.7" of travel and a 3:1 leverage ratio and a Fox DHX Air sees me with over 200psi in the main chamber of the shock just to get the correct sag on it… If I were 15 stone it would kind of render the air shock useless as I couldn't pump it hard enough for the weight of the rider.
There are plenty of 5" travel bikes out there with 2" stroke shocks fitted as standard, and even some with 2.25 or 2.5" stroke shocks too!