[R] generalized linear mixed models with a beta distribution

[Craig A Faulhaber]

Greetings,

I am interested in using a generalized linear mixed model with data that 
best fits a beta distribution (i.e., the data is bounded between 0 and 1 
but is not binomial).  I noticed that the beta distribution is not 
listed as an option in the "family objects" for glmmPQL or  lmer.  I 
found a thread on this listserve from 2006 ("[R] lmer and a response 
that is a proportion") that indicated that there was no package 
available for mixed effects models with a beta distribution at that 
time.  This thread also indicated that package betareg did not allow 
inclusion of random effects.

Does anyone know of a package or code for a generalized linear mixed 
model that allows a beta distribution?  Transforming my data might allow 
me to use another family, but I would rather not transform the data if 
possible.  Thanks for your help!

Sincerely,
Craig Faulhaber