That's a great idea, Andrew, shedding light on that kind of environment. You make great points and your deal (...waiting until 29...) was a lot like mine.
Gene, based on your original posts and sentiments (before everybody told you what a great dog you had! ;-))
I still think you should look for a rehoming option just in case, but if you do keep the dog...
Re-read all of Ed's articles related to your situation. I still read them all the time.
Get your schedule and your body clock ready. I get up around 430am and get in my harder exercise with the dog before the kids get up around 630am. That will be the only time you have to yourself for the next 18 years. If your dog is not exercising now that is the fundamental change you have to make now and later. You don't want a pressured-up dog in the house. Hard morning exercise, walks/fun with me and usually the kids when I get home, one relaxed "obedience walk" around 1000p or so to proof commands and get ready for sleep. Wife stays at home and is able to let her out a bit during the day. I'd get a dog walker for day stuff if yours will not.
Get a really good jogging stroller (for triplets?) or at least something robust enough for long walks. I use a Wike (www.wike.com) and I think it's better than anything else out there and I can also hook it to my bike with the rig I will use for my dog when she's old enough.
I also don't have house time with the dog when the kids are up. She's confined to the crate (75% of indoor time) or the kitchen (the rest of it).
Set up the "toddler" environment now for the dog to get used to. Baby gates. Drag lines. Prongs. Teaching the dog what's off-limits, limiting free time now for later when the kids will be up and about.
I personally am a big fan of crating in line-of-sight so the dog can watch me and my wife interact with the kids. I also crate at night in the bedroom with my wife and our baby. Ed and many people here think this is a bad idea, but you'd kind of have to see the set-up of my bedroom (she's basically tucked away in a gable of our upstairs converted attic...it's a real "cave"...away from the bed). I do think that is good pack time with the family and she's a very calm dog with no separation anxiety whatsoever.
Feed your kids first where the dog can see it/know it's happening.
Figure out a way for your wife not to shut the dog out once the kids arrive. If that's you taking them for a walk for a few minutes a day while she just interacts with the dog, make that happen.
Set up the interaction plan and make sure your wife is okay with it, too. The "but I have to walk the dog now" excuse will not work anymore. I'm actually pretty serious about this...be open about what you are and are not going to do and be flexible about accomodating it. Kids and wife first.
Make sure your dog plan has a backup in case there are any problems with your wife or the kids early on. There will be.
Scope out an animal behaviorist now and walk through whatever plan you're gonna use...and have them around once the babies come. I didn't do this as my kids were first but I would if the situation was reversed. I would like a second pair of eyes on the various cues the dog was giving off if something came up.
Cowboy up and get ready to give harsh corrections if you've never done it. Read Ed's article on giving corrections, etc. You want any negative interaction the dog has with the kids to be memorable for the dog in a very bad way.
Set up a fair environment for the dog, too. When the kids get aware of the dog never let them tease. Don't be biased towards the kids if they are messing with the dog, don't let your wife, either. I think kids can learn live and let live pretty quickly (2-3 y.o.).
Just my opinions. All this stuff worked for me, none of it is new, but maybe this is just another anecdote on it working.
And we had a big moment in our house today...my 3 y.o. put my dog in a sit, then a down. First time he ever tried that, and she responded right off the bat. He's still not housebroken, though.
I deliberately typed all this crap to ask myself again why it was such a good idea to get a dog???