I'm kind of surprised at the discouraging posts here. I know SME doesn't support it out of the box, that's why I asked on the contribs forum rather than on the main forum.
The situation is that I registered x.com, x.net, x.us, and x.info. The latter two (and really, the .net) are really registered just to keep someone else from registering them and being confusing. Of course, if the names are registered, they might as well resolve, but I don't want to spend a lot (or any, really, if I can help it) of money on DNS hosting for these domains. The free hosts I'd used in the past aren't free any more, so I though it was something I might pursue on the SME server.
Thanks for the afraid.org suggestion--I'll have to check it out.