There was an article about the C-123 in Aviatsia i Vreyma (1996-2) which had some details about the Pantobase Fairchild YC-123E as well as a photo of the YC-123E (Serial 54031) , the same shot as in Hesham's initial post and in C-123 Provider in Action (Squadron Signal 1992).
Fairchild YC-123E
The YC-123E had been an experiment in providing the C-123's with ability to operate wherever it might need to; on snow, ice, water, mud or rough un-made strips. It used the Stroukoff Aircraft Corporations own Pantobase system which were two high-stress skis fitted to the lower fuselage. The aircraft also had wingtip mounted floats and a fully sealed fuselage. All of these features gave the YC-123E the ability to operate from almost any runway surface available. The variant also incorporated Boundery Layer Control (BLC) benefits developed with the earlier YC-123D.
First Flight: 28 July 1955
Crew: 3
Maximum Take-off Weight: 24,500 kg
Empty Weight: 15,250 kg
Engines: 2 x Pratt & Whitney R-2800-99W (2,500 hp each)
Length: 23.5 m
Wing Span: 33.6 m
Height: 10.4 m
Wing Area: 114.7 sq m
(The piece also had 5 pages on the development of the C-122 -> C-123 -> C-134 through to the MS-8-3A project (with plan view of the latter) and Michael Stroukoff's developments with gliders as well as the Stroukoff involvement in C-123 variants).