One thing that may be worth considering is GWT.
We have been evaluating GWT internally and a conclusion we are reaching
is that it is significantly more efficient and
to develop and maintain with GWT that Ajax, JS, dhtml.
The best way to do get into GWT would be create value objects(column
names become class attributes) from ofbiz entity source.
We have also been evaluating using RIA. A clear winner for us was Flex.
There have been issues with it but.. exposing entities through XStream
was an approach we were thinking of going into.
I realize this is a bit abstract... but for ofbiz i feel, jumping over
Ajax libraries to GWT may give good benefit.
Harmeet