[R] Multilevel pseudo maximum likelihood

[Caterina Giusti]

Dear all,

I posted this two years ago, getting no answers or suggestions - now I 
am trying again, hoping something new is available in R.

I am interested in an application of linear multilevel model with 
unequal selection probabilities at both levels.

Do you know if there is an R function for multilevel pseudo-maximum 
likelihood estimation? Or is it possible to obtain these estimates using
the nlme package? In practice what I need is to insert in  the 
likelihood the individual and cluster level design weights.

Thanks in advance,
Caterina