As Airjockey indicated, if you do this, approach it from a hobby or educational standpoint, not a profit goal. A good , current, case in point a single engine Navion... 4000 hours of work, 190K invested.. Offered at 119K.
http://www.aso.com/i.aso3/aircraft_view.jsp?aircraft_id=102967
If you look on the For Sale page of the Twin Navion link you had, most of the twins are offered for MUCH less.. http://twinnavion.com/forsale.htm
Creating a group to purchase the plane & finance the restoration is a good idea, but a hard sell with those kind of financial numbers. You might also want to contact http://www.aircraftsystemsmanagement.com/ for advice.. They do Cessna reconstructions & would have a better real-world view of costs and difficulties in achieving your goals. Best of luck one way or another, though..