DOCBOOK: A XSL processor with better error handling than XT?

I am currently learning DocBook XML with Emacs and XT under Linux on a
memory constrained laptop, where I write the tags "in hand".

My question is:  XT only reports the first error in the XML file, and then
stops.  Is there another XML processor which reports more errors in a
non-well formed document, in order to fix them all in one swoop?

I have found the XSL language to be a very nice way to use tags in a way
that for some reason goes well with me, and reminds me a lot more of Lisp
than I would have thought (especially after having written perl to adjust
HTML code).  The XSL style sheets for DocBook are still early in
development - are there any efforts other than Norms own that work on
developing these?

Best regards,
-- 
  Thorbj鷨n Ravn Andersen               "...plus...Tubular Bells!"
  http://www.mip.sdu.dk/~ravn