PM BG.. if you know how to work the Cruise System or have an agent that knows how to work the system you can get HUGE upgrades for little or no extra. Some rooms on the boat they'll send you a price for, and you can negotiate.
I don't how true it is, but on our cruise one of the couples on the boat had one of the owner's suites.. 3 bedroom, 2 bath, private courtyard, balcony.. etc.. etc. and paid the same thing we did for our balcony on the back of the boat. Cruise company sent them a quote for the room, they sent back a note saying "No thanks, too much. We can't go any higher than 'X'" and the Cruise Company accepted their offer, about a 1/4th of what the room normally goes for.
We scored great prices on our room too, not as good as they did, but we still made out. Private Butler, Concierge, our own private dining room.. HUGE room.. yeah, BG spoils me, but I'm SOOOO worth it!