Gentle Requests: Would it be possible to include this in V8 please? Further as Bayes is better for multilevel/hierarchical models, could V8 have Bayes for count models (single level and multilevel) please. These two additions would be tremendously useful and also help stay within the Mplus platform avoiding using Bugs or STATA for these models, which are very common now due to richer data being available.
No - unless you are able to collapse one of the levels to multivariate model (e.g. if you have only 5 units on level 1 you can use a multivariate two-level model with 5 count variables instead of a univariate three level model), see User's Guide example 9.12.
You can alternatively run the two nesting levels (lever 2 and 3) separately with a two-level model and then retain the level with stronger influence.