As far as I know, portal does not support it specifically.
but if you want to build your portal with it, you can.
the layout is a good start : you can do whatever you want in it : it is built on html, jsp, etc...
you 'll have not to use the original portlets provided.
you'll have to adapt them, so they provide the proper html...
if this adaptation is possible (not for the portlets that yet use some ajax, I guess...).
this may be a lot of work...
but entirely feasible.
think that the JSR-168 and jboss portal allow to provide pages for WAP, ... so can be on Quirks Mode... just a question to adapt the content and the way it is provided to the client browser.
This was done in Jboss Portal 2.6.2 AS 4.2.1.
The only relevant changes are:
- removing the doctype declaration from the layout jsp
- forcing the header content on the layout jsp to have a height of 1px or so.