I used a simple mod for phpbb2 that I had modded heavily before abandoning it called Blender Portal. It could be easily adapted to our needs, and the way it implimented blocks was genius. Any stand alone script in the /blocks directory could be used as a side block, so no adapting a script to work with the portal. Any script already worked, and you could still blocks from phpnuke, etc.
I might tackle it, but here is the basic design if someone wants to start:
portal.php
create DB table PAGES
with fields "html code" "Page title" "Page description" "Keywords" "Unique ID"
call pages in this form portal.php?page=Unique ID
when page loads, call database, get page info, replace title, desc, and keywords in headers and replace html block from portal template
That would be a basic portal minus the admin page you have to create, then you have to impliment blocks, etc. If someone who has done plugins or mods for punbb wants to work with me, we could knock out a rough version pretty quickly.
Max