No luck on the hilt yet, but I did stumble across this version of a nimcha on the Therion Arms page. The blade is listed as 'napoleonic', and at 24 1/2" is identical in length to the one I just bought. Due to the poor angle in the pictures posted by the seller it's impossible to be sure, but it looks awfully close to me. Not also the slight humpback profile to the hilt, peraps due to the profile of the tang? Anyway, more food for thought.
PS -- I hope I didn't violate any rules by posting these pics. I did give credit for their source, and the item in question was already sold.