Beta-binomial distributions with lmer?
Well there are papers that argue against this sort of ad hoc approach. See for example http://psychology3.anu.edu.au/people/smithson/details/Pubs/Smithson_Verkuilen06.pdf which is about beta regression for bounded dependent variables.
David A. Fournier P.O. Box 2040, Sidney, B.C. V8l 3S3 Canada Phone/FAX 250-655-3364 http://otter-rsch.com