Since portage contains already ximian-connector and ximian-openoffce, it would be good to include Red Carpet (from source code). Why? Since ximian-connector, is only avaiable in binary form for other distros (Feudora, Suse, Redhat, ..) and in source code format for all others, we are going to need it sooner or later.
what is the purpose of red carpet in gentoo?
To easily get software from Ximian running?! Ximian-Connector is only available via red carpet (at least, when I last checked). Maybe there will be other products in the future, I'm thinking about iFolder or even GroupWise, that might be only available via red carpet.
connector was and especially is available just fine (just do an emerge search). I don't see the added value really, people shouldn't be using an rpm based solution on a Gentoo machine : that's a recipe for disaster.