On eBay, some company called 'Country Covers' or something is selling some nice Arktis Windproof/Waterproof outdoor smock-type jackets. They're a bit pricey and might well be in SASS price range unfortunately.
OG smocks seem a nightmare to get hold of.
Height 200 smocks seem a nightmare to get hold of.
Combine both and I doubt you will have a non-nightmare. Money might be the only way.