[R-sig-ME] parameterization for partly nested design with repeated measurements

[Kay Cecil Cichini]

dear listers,

i'd very much appreciate help with setting up the right parameterization 
for the following design:
4 regions, in each region 3 to 12 schools, at each school 2-4 classes 
and each class tested before and after intervention, yielding a bimomial 
outcome (pupils that passed / not passed a test).

i'm interested in differences between before and after (factor = 
"interv") intervention outcomes (X = passed, n = passed + not passed) 
and in the interaction region * interv.

i tried with:
glmer (cbind(X, n - X) ~ region * interv + (region | school / class), 
family = binomial)

and with:
glmer (cbind(X, n - X) ~ region * interv + (1 | school / class), family 
= binomial)


i'd be happy about comments on the parameterization or any ideas.

yours,
kay