Your best met may be to have a go at making a pair yourself.
I used to own some, they are really nothing more than a pair of ribbed mudguards, a hinge and a rectangular metal box cut to meet the line of the guard. The handles on them are 50's style kitchen cabinet handles which can still be bought new. Postage from the UK would be obscene, when added to the cost of a set if you can find them. I paid £80 for mine and that was about 20 years ago. I don't think you'll get a set any cheaper these days.
Cheers,
Iain