Well this is what I know, (Allentown and Bethlehem, Pa) building inspections done on houses I help build require illuminated switches at the top and bottom. This is why we wire stair/hall lights such that the 3-ways are at the top an bottom. Illuminated 4ways are differcult to find(very expensive).
Ok this is what I found, in BOCA:
1207.2.1 Controls: The control for activation of the required
stairway lighting within a dwelling unit shall be operable from the top and bottom of each stairway without traversing any step of the stair. All switches that control interior stairway lights shall be illuminated switches. The illumination of an exterior stairway serving a dwelling unit shall be controlled from inside the dwelling unit, unless continuously illuminated or automatically activated.