You, sir, get a billion internet points!
I just did this with my real accounts and all is well! I was able to rename my existing @live.com account into an existing @outlook.com account.
Furthermore, I was able to keep EVERYTHING. I kept my 25GB of free loyalty SkyDrive storage, emails, history, aliases that were already set up in the @live.com account, contacts, message history, Windows Phone app purchases, Xbox avatar and points, Bing
rewards, etc.
You are a hero.
Microsoft, on the other hand, shame on you and your disgusting excuse for customer support. You have a hundred engineers over at Redmond and it took an ordinary user to rise up and fix your disaster. I was told over and over that there is no solution by
SkyDrive staff, Hotmail/Outlook staff, and forum moderators. This kind of behavior makes me want to trade in my Windows Phone for an Android. You have treated your customers like ****, and we won't forget it.