Marblehead has several condos that operate essentially as stand-alone homes.
The reason has to do with the zoning requirements for a single-family house vs a condo.
In fact, I have one for sale at 9 Togan Way. It's a condo but attached to another condo and both function as single-family houses.
This house/condo is priced high for its size, however.
Check out 9 Togan Way, Marblehead.