Deluxe loft space? - whose using the term? - sounds like marketing hype from a loft conversion company with attitude.
There is a Building Regulations issue with what you are proposing - if you put a permanent staircase in there, the space counts as habitable space. If this room is then the second floor (ground, 1st, and now 2nd) you will be above the height at which you need to satisfy the fire escape regs for domestic dwellings. This is usually done by changing all the doors that adjoin the landing and hall (habitable rooms - not cupboards) to make them fire doors. You will also have to satisfy Building Regs that your new loft meets the thermal insulation requirements.