I'm about to paint with a pretty broad brush here, but after thinking about it you may find you agree with me ..............
Why would anyone limit and/or disadvantage themselves in the world of home defense by using anything but a shotgun? A short shotgun, a big bore shotgun (12ga preferred) and something other than a slug for maximum shot placement at short distances. A slug requires much more proficiency than buckshot, 00B - #4B. Unless you are a very proficient shooter, why wouldn't you choose either of these?
At almost any distance withing the confines of most homes you will not see a distance where shot of any size will expand to a point of wasting pellets. I don't know of anyone who has an interior room longer than 30 yards, do you? The slug (most of them) also will usually be more apt to penetrate interior walls where other members of the family might be, or maybe even into a neighbors house or apartment not to mention that if you do know someone with a room 30 yrds long, you're pretty likely to miss with a slug at that distance anyway.
I think if we're honest, we will accept that by far the majority of home owners, even those who are ready, willing and able, and even semi-practiced to protect their home and family are not expert shooters. If we can accept that idea, it should be readily apparent why the slug is not the best choice for home defense ammo for most folks. It must also be accepted that in any event of a home defense situation, the moment will be tense, nerves will be at high level, and with that one big pellet, some amount of aiming (or at least a concentrated pointing) will be required increasing the chance over that of buckshot of a miss.
In the final analysis I just don't see how any shotgun/slug combination would be a better choice than most any shotgun/00B combo.
What do you think?
On edit: Someone else mentioned that he's not likely to follow a bad guy back outside in any event. I've got to say I agree with that 100%. If I've been successful in defending my home and family, why on earth would I expose myself to the outside and any unknown attackers?