Wow, lucky guy!
My advice is pretty lame but here it goes.
I'm learning bikes are a very personal item. Besides, I tend to do things on a budget so I don't really know much about bikes over $1400.
I'd get a bunch of the smallest and lightest stuff I could find as mentioned above. Even then I'd have lots of money leftover!
What I'd look at for gear would be things such as the Thermo-a-Rest NeoAir matress, packs up very small and is about 415g. Sounds like a paper bag when you move though.
Get an expensive sleeping bag rated for whatever you require. The more expensive the bag the smaller it packs.
Then I'd go for an ultralight tent, one of the MSR Hubba Hubba HP's. Or similar / better for you.
I'd replace any clothing you might have been wanting to upgrade or exchange too. Stuff gets old and we tend to get used to it as it ages, new shorts, helmet, pants, gloves, shoes, etc. might just make your ride that much more enjoyable!
Check out cycling GPS units, perhaps one of those has been on your wish list and you've forgotten about it.
Replace any of those smallish items that you might think are on their last legs, or over the years have been improved upon to be lighter or better in a way you think is worth the upgrade. Small items add up as shopping list gets longer. I swear it's the small items that I always leave me looking at a reciept wondering where all the money went!
Maybe get an extra tire or two and some replacement parts so in a couple months if a tire blows you don't have to tell your wife that you spent another sum of money on a new one.
When you get your bike built get it with one of those fancy hubs that
are also a generator. I'd love one of these. Something to look at maybe.
Set aside another sum for trip emergencies if you think that's a good idea, might not be something you need to worry about though.
And finally, if it was my wife I'd have to spend some of it on her even though it was a gift! I bet she'd like another nice dinner or a weekend at a B&B!
Then with what's left, get the bike.
Good luck!