You should be able to get everything working on Joyent systems, as they use Virtualmin extensively. You may need to contact them about solaris-specific package management issues though, as Virtualmin is much better tested on Linux (specifically CentOS, Debian and Ubuntu). And those operating systems provide mailman packages whose locations Virtualmin already knows about.
Don will be getting back to you all on this with more details, but briefly: he bought a hour's system administration from Joyent for them to install mailman for us. I'd like whatever they learn to be shared with you folks too. We'll let you know what they found out, and how they configure mailman. Maybe they'll make a pkg available?
I'd be interested to know what kind of site architecture you are trying to setup there, as that would help me to make suggestions about the types of servers to use.
Basically we're building a "community" site consisting of "members" and "projects". The community is composed of members, "Digerati" living in Santa Fe, NM: scientists, urban studies experts, visual artists, ethnographers, analytic journalists and so on .. mainly tied together via ideas of cross-discipline studies, and inspired by the Santa Fe Institute .. the birth place of Complex Adaptive Systems 20 years ago. The projects are specific design efforts by the members .. i.e. projects are made up of subsets of the total set of members.
So in terms of site architecture, we will need the usual content management for the organization itself (front pages, newspaper/blog, newsletter, howtos, about, FAQ), along with sub-sites for members and projects. Our site design/sociology is not firm yet, but getting there. We may, for example, use sub-domains for the projects and just web/wiki pages for the members.
In addition, some projects need the ability to install open source software that is not in the virtualmin scripts. One example is Pootle, a translations system that lets communities translate existing sites into several languages. We have one project now which wants to translate the NetLogo simulation software, for example, as part of a project with Cuban scientists.
So our task is to create a mapping between our community structure and virtualmin facilities. And to provide help for projects needing to install and create new software. Indeed, one reason we chose Joyent was its programmer-friendly services: svn, RoR, Django and so on. We decided on dedicated rather than shared hosting due to root access for installing unusual packages and for the increased performance.
Here’s a pointer to a wiki containing an example of the projects: http://sfacc.pbwiki.com/ and here’s a pointer to our current, under construction web site: http://www.santafecomplex.org/