Hawkins & Powers has a fleet of ex USAF
C-97's at their base in Greybull, MT
and has one set up as a forest fire tanker (Tanker 97), I don't know if it is still being used. The others were supposed to be converted to tankers but the last I heard they are just sitting at the airport.
The Berlin Airlift Historical Foundation as a C-97G in flying condition. It is based at Floyd Bennett Airfield adjacent to JFK
and it is being set up to tour the country in a remembrance of the Berlin Airlift.
These are the only 2 flyable C-97's left.
I believe the Israeli Air Force models were C-97's that were converted to swing tails for the IAF
The C-97 and the 337 are basically the same aircraft and if someone who can afford it, like Boeing and convert a C-97 to a 337 for display purposes at the Museum of Flight.
This would fill in the gap between the 307 and the dash 80 707 which are now both on display as to Boeing's evaluation in pressurerized airliners