What an interesting idea!
We were trying to figure out a way to make split weeks and the subsequent reduction in airfare work for us also. Maybe this can help you, although it wasn't
quite using the split back-to-back.
We just bought the two holiday weeks and wanted to see if we could buy a third week with the express intention of splitting it every time to add around the two weeks so as to flesh out the Christmas school break as well as travel on weekdays.
Here's what they said they could do at MAW. we could do it - especially the first part (week before Christmas) as that is much less utilized. The harder part is after New Year's, and especially the first time we did it, as it goes into the next calendar year plus it is used more. We'd have to book the full split for 2011 to utilize it. We would have to pay the fee, but they seemed to think the idea was pretty doable, except you couldn't count on it each year as it is subject to space at the resort. They don't have to have another match up with yours, but they do have to have availability for that week. They said it was much better to simply book a week (so while they try to discourage you, they will book it if it is available - and were totally able and willing to book us had we had the extra week)
In our case, we'd have to book the 2010 additional week either as a split with part of it lining up with the holiday weeks and the other days earlier in the year, or we'd have to book the 2010 week in full the week before Christmas to use it before 2010 ends. Then they could already book the first part of the split in Jan 2011 to occur AFTER our two holiday weeks - and then go on from there each time booking the split for begin of Jan and right before Christmas week. We're still thinking resale for this purpose
Please do let us know how it works out!