Yes, we also did a week the first time we went. Didn't want to take the kids out of school for too long, and as I'm an IT contractor I couldn't afford two weeks not working. Still cost less than a week in Portugal the previous summer though.
We didn't do Universal at all -- got a 5-day hopper plus and did AK, MK, MGM and Blizzard Beach. Went back this year (for two weeks) and used the remaining days on the park hopper (MK, Epcot, DTD PI and a round of minigolf) and also did US, IoA, SW (twice) and WaW.