Sounds like you want to make a shared view, as a user control. Then you can use the MvcToolkit to render the shared view, like so:
<%=Html.RenderUserControl("~/Views/Shared/RSS.ascx", RssData) %>Personally, I build separate RSS views for each controller... I usually end up tweaking them a bit so they're each somewhat different anyway. I don't really like the method I showed you above, it seems a bit like a hack. I mean, you'd have to create the RSS view for each controller anyway, then make a call to the RenderUserControl to render the shared view. Perhaps there will be a better, more baked in, method of doing this in the future.
Did I answer your question(s)? Phweew...