I worked for the Rix Centre @ UEL and various of the other partners on a 2 year PACCIT (DTi/ESRC funded) research project looking into a range of issues surrounding virtual learning environments and eportfolio for students (16-25) with cognitive disabilities - specifically focussed on those with severe and complex LD but also including learners with PMLD to a limited extent. I can't adequately summarise findings and output in a single post, but I'd like to contribute here if we can break the discussion down a little.

There's more info and background to this research which finished early in 2006 here:

http://www.paccit.gla.ac.uk/public/projects/apple.php

http://www.thebigtree.org/roots/html/projectapple/index.htm

Simon