However, to take this in a slightly different direction....
Ever heard of Magnum Research (the folks who make the Desert Eagle)? They have a revolver they call the "BFR." They insist that it stands for Biggest Finest Revolver. Really.
Here's a chance to mix your metaphors, so to speak.
The one in the picture is their BFR .45 Long Colt/.410 Revolver. Put in two or three 410 shot shells with bird shot up to buck shot type loads, then have the last couple of rounds be .45 long colt. By that time the bad guys are either on top of you or trying to get distance. In either case the bullet would have advantages by then, if you have to go that long in combat.
Of course, I'd still keep a conventional shotgun available. If you go beyond the 5 shots in the BFR you're in a serious firefight and you DON'T want to take time to reload a wheelgun without a speed loader!
More seriously, look at "less than lethal" shotgun ammo from several companies, among them Blammo Ammo. They have some very interesting loads for 12 gauge that will scare the hell out of the perps (and kill them if they're close enough). Dragon's Breath is one of my favorites, particularly at night. 90 feet of flame. If the sucker is still coming after you let that off then he means to kill you and the slug in the next shell is automatically justified.
Finally, both seriously and realistically pick a pump shotgun, either Mossberg 5XX, Remington 870, Ithaca 37 or Winchester 1300 would all be fine (I listed them in personal preference, but I have NO expertise). Then it makes sense to me to load it with successively more lethal rounds, starting with something like "rock salt" or rubber bullet loads, then bird shot, then buck shot and so on. Then practice with all of the loads you might need to use and have everyone else in your household practice with it and be 100% familiar with all of the safety and operatioin features of whatever you end up with.
Finally, with whatever you get, hopefully just the sound of you racking a pump shotgun will convince any intruder that he wants to look elsewhere.
