TWiki has been forked, and the fork named Foswiki. For details about the history of the fork see http://foswiki.org/About/WhyThisFork . Foswiki has by now released versions up to 1.0.6. I'd like to see them in portage. See http://foswiki.org/Download/WebHome for current version. I imagine that it should be fairly simple to turn a current twiki ebuild into a working foswiki ebuild with little effort, but haven't tried (yet). By the way, twiki has released 4.3.1 by now, whereas 4.2.4 is the latest in portage. Maybe updating that at the same time can save duplicate work. http://twiki.org/cgi-bin/view/Codev/DownloadTWiki has the latest version.
Second request about the version bump for twiki should be a seperate bug, so I'll go ahead and make that one for you.
See bug 279318 which covers the request for a version bump on twiki.
Would also like to see an ebuild for foswiki. Haven't found the time yet to look into it myself, though.
Created attachment 224753 [details] ebuild & related files for Foswiki 1.0.9
I took the most recent TWiki ebuild and hacked it to get it to install the most recent version of Foswiki. I've not hammered on the resulting Foswiki install too hard yet, but so far I can verify that it creates a wiki that can be configured and accepts new users.
Created attachment 224757 [details] ebuild & related files for Foswiki 1.0.9 some minor tweaks applied