The following series of links are various re-enactment groups and individuals who have attempted reconstructions of Roman Saddles.
Caerleon's Roman Legion
Museum Reconstruction of a Roman Saddle and tack on a model horse
Unfortunately this picture didn't come with any explanation of where the museum was located.
Illustrated with Roman friezes and statuary presented along side the reconstructions for comparison.
Very detailed site with photos of his reconstructions and several article on different aspect of the calvary's role and function.