First, don't worry so much about business class vs. first class. First class can be hard to get, but business class is just fine. You will get great food (by airline standards), wine and champagne, big sleeper seats, noise-cancelling headphones, really, you will be fine. You might even like it better since the first class seats can be so private that you can't even really communicate easily.

Now for the bad news. Upgrading coach fares is very difficult. You can usually only upgrade fares that are well above the cheapest. Buying an upgradeable fare can often be more expensive than discounted business class.

Now for more bad news. Your USAir and Chase points are not really combinable. You can transfer your Chase points to United, but not to USAir. If you had enough for a ticket on USAir, you possibly could book one ticket on the same Star Alliance routing with US points and one with Sapphire points converted to UA. (Also note that you said you would have "27,000 US points." Not really. You will have 18,000 and she will have 9,000. You can't combine them.)

So you're going on your honeymoon in the back of the bus? Wait, not necessarily. Dr. Redtop has a prescription.

Get each of you a United Mileage Plus Explorer card, which if you do it right, will get you 55,000 United points each. (Be sure to do it the right way, there are tips in the thread on that card.) Now you can transfer 45K Chase points to each of your United accounts and - voila - you have 100K points for a business class ticket!

More good news. Based on my limited experience, United is the easiest airline to search for award availability.

Hopefully you don't have some reason not to get the United cards. Note that you get the points with just one purchase; you don't have to meet a minimum spending requirement.

So surprise - yes, you probably can do this for free! Well, there will be a few hundred dollars in taxes and fees.

Another suggestion - perhaps - get each of you a USAirways mastercard. 40K for signing up and 10K each year when you pay the $89 annual fee. In about 5 years you'll have enough for a second honeymoon.