The California Automobile Museum (location) in Sacramento has at least three. I have been there yet, but it might be a potential stop on our California tour in March. The M-38 and CJ-2A were photographed by Jack Snell in August of 2013 (more great jeep photos by Jack in his photo stream).
This 1951 M-38 looks good:
This 1945 VEC CJ-2A looks very good:
The museum also has a 1943 GPW which was photographed and posted here along with other images from the museum. Below is the photo of the GPW: