One example I can think of comes from outside the museum world.  The
Deafness Research Foundation has a "club" called the Centurions, whom I
believe pledge $1000.00 per year toward DRF's operating expenses.
This is obviously done in full recognition by the donors of the
difficulty many organizations have in funding non-sexy (or ego
building) projects and activities.
 
Perhaps the problem is that most donors don't really care about the
organization they are supporting?