The reason I would like to be able to import a compiled stylesheet is
not to use a functional library, but for performance.

I have this kind of setup:

A -> B -> C

Stylesheet A imports B, which imports C.

B and C are both reasonably large stylesheets.  A is generated per
request, is quite small and overrides specific templates in B or C
depending on the requirement.  I keep compiled copies of B and C in
memory, so when A is not needed I can just use the compiled version.
However, when A is needed, B and C must be parsed and built each time.

The fact that in XSLT the 'project specific' stylesheet must import the
'common' stylesheet, is why we really could do with a way of compiling
up that common stylesheet.

cheers
andrew