Thanks for this valuable insight. You have confirmed for me that Wx is probably the right Perl/GUI route for me to pursue. If it works with JAWS on Windows, it certainly should work with other ATs, as they would all be using the same MS accessibility API.
I am very interested to that Java/SWING isn't as accessible as is perhaps made out. It would be so nice if it transpired that it was easier to code accessible GUI applications in Perl than in Java. (Market penetration would still be an issue - most computers ship with a JVM, but I haven't seen too many non-UNIX systems that ship with Perl :-(