So I'm happy to announce that this long-standing RFE since August 2005 is finally implemented in the latest Hudson 1.91 (changelog.) It comes with FishEye, ViewCVS, and ViewSVN support. (Normally I'd do FishEye in a plugin, but this feature has such a small UI surface that I thought it's OK to do so in the core.)
To configure this, go to the project configuration, select the SCM browser type you have, then enter the URL of the site. Just to show that I did my due dilligence, the screenshot shows what happens if you make a typo:
It's very common to have multiple jobs that work with the same Subversion/CVS repositories, so as long as one of those projects are configured, the other projects will automatically pick up the setting. That's why it's called "(auto)", not "(none)". So there's no need to go through all projects individually.
Finally, as with everything else in Hudson, this is extensible. So a plugin can be written to make Hudson support other kinds of SCM browsers. I'm planning to write one for java.net SCM browser, so if you are interested in supporting other kinds, please let me know and I can help you.