The XSLT + AJAX data grid described over on XML.com looks very interesting and solves a real and very common problem. Be sure to try the examples: there are lots of features there.
The data grid has linear performance scaling with the size of the data set whick is OK for many applications and better than most naive implementations.
The greatest advantage to using XSLT for a JavaScript widget is the flexibility it provides for instantiation. Most Ajax-using web developers will be working with a server-side component/language, and having the option to reduce a client-side JavaScript decoration step to improve performance is nice, though it comes with a bandwidth price. In many projects, developers may be faced with a mixed bag: they may have a need for some large dynamic datagrids, which can only be originated on the server, as well as some smaller hand-coded tables, where a less-rich datagrid would be fine. For instance, developers might not always want to capture the fact that a user changed a column’s size and store it as a preference, but even for these less-rich datagrids, developers do want them to look and feel the same. The XSLT approach gives the developer an opportunity to choose either a client- or server-based technique to achieve a similar result.
I must have a closer look at this.