The Iowa Court of Appeal recently handed down a decision in a divorce case entitled In Re Marriage of Munger affirming a trial court's finding that a week-to-week rotation in a joint physical custody situation is best agreeing that it is predictable and avoids mid-week juggling of children and school work. See
http://www.judicial.state.ia.us/court_of_appeals/Recent_Opinions/20070411/7-157.pdf
This arrangement tends to work best for older school-aged children but not necessarily children within the "tender years" parameter, typically age five and under.
The Iowa Court also affirmed the use of a "special expense" account where both parties would deposit a certain amount each month to be used for the children's expenses in light of their inability to communicate regarding the same.