Streaming XML Processing

Is anyone aware of publically available implementations of XPath, 
XQuery, and XSLT that operate in a streaming manner i.e. in a single 
pass over the input.

I'm especially interested in Java implementations, and completeness of 
implementations (although a sufficiently large subset of standard 
functionality would be useful). If you can comment on the completeness 
of an approach, that would be most useful.

I'm aware of XML-TK for a subset of XPath, does anyone know of more? The 
academic literature mentions a number of systems that do not seem to be 
downloadable.

Thanks
George Russell