Some people do that with a series of cookie-setting redirects going through all the possible domains. It sounds ugly, and it is ugly.
If I remember correctly this was implemented in openacs 3.x (which does not make it less ugly).
is anyone extensively using host site node mapping?
Not yet, but I might want to do so later.
In general I think the host-node mapping stuff is very interesting for small OpenACS sites. Having the possibility to quickly add a site with its own domain to an existing OpenACS installation is great, e.g. if you want to do your friends a favour who need a simple low-traffic site with some functionality.
It would be sad if OpenACS lost this functionality - so: yes, your fixes are highly appreciated.
