Winooski - 2:09 pm on Jun 20, 2011 (gmt 0) [edited by: goodroi at 3:38 pm (utc) on Jun 20, 2011]
I think this is fairly clean (and I have no affiliation with it other than being a consumer of its services).
Our local alternative weekly here in Burlington, Vermont, is Seven Days, and its official URL is 7dvt.com. They also have a URL that's 301ed to that URL, sevendaysvt.com. When I search for "www.sevendaysvt.com" [google.com], their main listing shows "www.sevendaysvt.com/ - Cached - Similar", and there's the additional line, "More results from sevendaysvt.com »".
However, before we start wringing our hands, I'd want to know if there are other signals Google could be using to authenticate the alt-URLs a bit, e.g., IP address of the domain server. It's not clear to me yet that this is a gaping hole begging for spoofers to exploit.
[edit reason] Fixed URL [/edit]
[edited by: goodroi at 3:38 pm (utc) on Jun 20, 2011]