Would it be possible to make a continuous-use Item with the spell Guards and Wards? AFAICT, the answer seems to be yes. It can´t be made permanent with the permanency spell. But a wondrous item should work.
It would be a continuous spell effect item, costing spell level x caster level x 2000 gp. Spell level is 6, minimum caster level is 11, so it would cost 6 x 11 x 2000 gp, or 132,000 gp.
It might seem strange to want this spell permanent, but if you are a high level wizard or even a lich, you could probably care less about web-filled staircases, misdirection effects or illusion-hidden doors. The fog is more a nuisance - if you are doing some magical research, 5ft. visibility is probably all right. If this is what it takes to get a little privacy...
Stefan