This is actually "k's mom" Congratulations! You and your wife know if deferment is best for you or not. It sounds like you know it is not right, so follow through on your dream. Just be prepared for a lot of sleepless nights (no kidding, right?) and assure that there is a great deal of support for your wife (family, church members, etc...to do laundry, clean, feed and change the babies, etc..) Yeah, I know you will need support too, but don't expect a lot of special treatment...you will have to be expecially loving and supportive of your wife and be prepared to be rather ignored at times. Regarding special promotions, most major companies have such specials. I know that Pampers, Similac, and I think Babies R Us have specials for multiples (freebies, etc...) You just have to write/email to ask. Also, try to track down a multiples support group in your area and/or get a subscription to TWINS! magazine. They will have more detailed and informative information.
I would mostly be concerned about any potential moves for school. As you know by now, triplet pregnancies are most definitely "high risk" which means you may be a parent sooner than you think, and moving and changing doctors may be impossible and dangerous for your wife. Your wife's OB can give you a better idea of what will be best. From my experience, family and friends are always offering to help out...and mere acquaintances seem to love holding and helping with babies, especially multiples. So, I say that you and your wife need to practice putting people to work now. When someone calls and says, "Can I help?" Say sure...you can do the laundry on Tuesday, or bring us a week's worth of meals on Sunday, or come by to feed and rock the babies while my wife gets a nap on Wednesday and I go to class. For out of town relatives (especially grandmas and grandpas), schedule them at intervals, especially if they want to "help" for a week or more. Just make sure they are supportive people who will be comfortable taking care of babies, and not expect to be chauffered around town to all of the tourist spots.
Best wishes, and best health to your wife.