Although charities cannot be sold technically, we are searching for a
non-profit organization (US) / 501c3 that is either closing down shop
or has already done so but still has an active status with the IRS. 
The charity needs to be 10 years old or older and willing to let our
group assume governance of the Board and administrative and managerial
duties for the charity in return for
expenses (reasonable) incurred in establishing the charity. 
Guidestar.org and the Publication 78 database at irs.gov provided no
answers.  We've tried to keep the search quite but we've had to ask
around to several state non-profit
organization assocations as well as the Urban Institute. Any suggestions?

Hi, I've gone through this myself. There are a few law firms that
specialize in non-profits. I'd suggest calling them and asking to put
the word out. I may also have access to one that would work for you,
but it is not 10 years old.