Aviation artist Skyraider3D has kindly tipped me off that the Royal Thai Air Force Museum have now made available a series of RTAF history documents in downloadable pdf. Although the text is in Thai the documents contain several interesting photographs and paintings showing many different aircraft types in Thai service.
The combination of colour scheme and markings depicted in the 'Oscar' painting above is new to me but I don't know how reliable it is. None of the paintings appear to show the White Elephant insignia.
I am grateful to Skyraider3D and the RTAF Museum.
Image credit: © RTAF Museum 2008