This is a really good question, which I have too been thinking about some time. More generally, is the way Matthew has done the right way (tm) to go when you want custom front pages for any packages?
I think one probably wants to have a custom front page for subsite, but often this is also the case for some other package instance, such as forums.
Some documentation concerning these things would be very nice to have, as it's the ease of use in the real world that is going to make OpenACS more widely adopted.
