Re: Vanity Height
Normal vanity height is around 27", kitchen countertops are at 36". 42" is too high for anything but possibly a wetbar where you'd be standing. My recommendation would be to pull the cabinet you've currently got and install something that is at a more reasonable height. You might be able to modify the cabinet you have, but without seeing it I can not comment on it. Under no circumstances do you want to build steps in the bathroom, you'll be asking for trouble if you do (i.e. extremely dangerous! ).
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!