BWB, I tell my clients, "If you got the money, honey, I got the time." That's what it really boils down to. If you've got a couple hundred thousand burning a hole in your pocket, I'll build you EXACTLY what you want.
Bill is right - you're talking about a semi-major reno. Where to put the new stairs? What do you do with the old ones? (what is the relation between the new stairs and the old ones?). What happens outside? .... not an easy little weekend job.