Although I'm sure they could get beaucoup bucks for a one-night stay in Cinderella's Castle, I think it'd be great to keep it as an ongoing contest where, at any time, some lucky family or couple would get the suite for a night. It can be a completely random choice based on people's hotel check-out dates-everyone checking out on, say, October 17th, with a group of 4 or less, gets to be in the contest, and winning includes any assistance you may need packing up earlier than expected to get to the castle, and the option of "gifting" your prize to anyone you want for the night in the event you can't or don't want to accept the prize for yourself, so at least you get the thrill of telling someone else they get the gift.*
So many people complain about how costly a trip to WDW is, and those comaplints are not entirely unfounded. Something like this would be a great public relations move for WDW; they could literally promote the contest for years. Everyone has just as much of a shot as anyone else (provided their party isn't too big, in which case...I don't know, maybe a family of 6 will just have to split up for the night. Wouldn't THAT make for fun holiday dinner fights as the kids get older?) OR, if they really want to be super-swell, they could use it as a Make-A-Wish Foundation gift.
*-I also originally thought of the random choice of guests getting the suite could be based on using Disney's Magical Express. Since they're handling your bags and everything, the pre-approved party could just have their bags sent to the Castle instead of to their hotel of choice, and they wouldn't need to worry about packing earlier than expected for their last night in WDW. The only dillemma to that concept is-once you spend a night in the Castle, how many people would be happy spending the rest of their vacation anywhere else? It seems like a vacation-ender to me.