I have been thinking about this, not sure I have ever really seen it, but is there any reason you cannot just have a bumpout on one of your end walls to be the stairs? all you would really need is the two door size penetrations of the wall, so structurally it would seem simple, and thus not waste foundation or interio space?
the total bumpout would be 4 feet at most?
If its cantilevered off existing joists beams the only issue I see is water ingress if they are open to the elements rotting under the floor
If they were enclosed it should not be an issue
Floor joists usually run parallel to the end wall so simply extending them will not work if the door and stairs are on such an end. At least the way I interpret the description, that's what I see in my mind. And it's never as good as a drawing.
umtallguy, can you flesh out your description some? Fill in some details as to how you visualize that 4 foot landing to be configured/supported.
I could see a bumpout on the side wall where the joists could be extended, but I would also be concerned about weather and water getting past the wall and under the interior floor
(http://farm4.static.flickr.com/3410/3471244295_3158368148.jpg)
is the best picture I can find on google of what I am thinking of.. I guess you could put a post in the upper outside corner.
Just something to reduce foundation footprint mostly, and keep it from getting into the middle of the room layout, though I suppose being on the end would require a hallway, and doesnt work well with multiple bedrooms, may work nicely with a loft though.