Is there a read-made virtual machine (for VMWare, for instance) configged with Subversion?
Not that I know of. I'm building up a machine to sit in the attic and serve files. Subversion would be a useful addition.
Might I suggest using SME Server for such a task? It's a Linux server system based of CentOS, that is managed primarily through an easy-to-use web interface. It includes the usual FTP/HTTP/Samba file sharing options. Additionally there are several contribs made by the community. Including Subversion and Trac integration.