I am looking at a Profile Design H2O stem that requires 50mm of steerer tube. So guggino88 can quite easily have a stem that is 50mm. There is 1 answer to the question of "Is there such a thing as having a too tall steerer tube?". That answer is yes but you are no where near being too tall. Manufacturers usually have a max. height of spacers used on a steerer tube. Depending on your physical needs and/or riding style -- the steerer tube may or may not exceed the limits. For example a certain carbon fork manufacturer allows up to 25mm of spacers on their 1" steerer tubes but allow 40mm of spacers on their 1 1/8 carbon steerer tubes. A alloy/steel steerer tube should allow even more spacers if necessary.
So -- no problem with your setup. If you change to a stem that is less than 50mm then just make up the difference with spacers.
You do need to make sure that the steerer tube and the top cap are no more than 5mm difference between them. If there is more than 5mm then go to a stem with less height.