Found these at Walmart today. Hats and sweaters were $1.88 each. They also had Christmas stockings in all those patterns, but I wasn't sure I wanted to fuss with those. The Santa jacket was 2.99 and in a different place. They have decorations on the front and a hanging clip on the back that are both hot glued, but I've had good luck getting those off knits pretty well using an iron.
SweatersXmas22 by Kenai Queen, on Flickr
There is no stretch in the neckline area, so it will mean slitting it up the back, but I think it will work on the RH girls. Pretty sure they are too tight in the bust for SmartDoll, but the hats might fit them.
Also, I meant to post this pic of Agatha Primrose in a pair of Ken doll pants and a leather jacket from Elf on the Shelf. Not a perfect fit, but not terrible either.
AdaInKen by Kenai Queen, on Flickr