What we love about ours (http://www.hitecpet.com/powerpetdoors.html) is that it only opens in reaction to the pet's collar, so no other critters can get in and out. It's three-way lockable with the push of a button, so it we can let them out but not in, in but not out, or close it entirely. We've had it two years now and had to replace batteries in the collars a couple times but so far, so good. Our dogs are 60 and 75 lbs and get through it easily. I could see it being trickier for really big dogs.
That looks very cool and certainly addresses the security issue!
Unfortunately, looks like the largest size is way too small for my guys, plus mine cannot wear collars when loose together (as they always are) due to the strangulation issue (they play biting games roughly, chew on each others throats). They are tattooed/microchipped for ID purposes and do wear collars when we travel when they are supervised.
But may suit OP, or those who live in sketchy areas.
Houndhill...IIRC you have Irish Wolfhounds? People doors are their dog-door sizes, LOL! I've had mostly giant dogs too, you just can't do dog doors for giant dogs. I do like the powered dog doors, in many areas it's a decent safety option. In areas like mine I used to get called often to come de-critter someone's house because some adventurous wildlife came visiting. Often skunks, possum or coons...once a fisher. *That* was a fun visit.
You jump in the saddle,
Hold onto the bridle!
Jump in the line!