Extremely. Jealous!!!! My palomino Gelding sort of does this too, but not to this extent. IN winter mainly but sometimes during fall/summer he gets some spots on him. I don't have any pics, but I think it's just the coolest thing. Also, in his mane/tail, instead of being just white, he's gotten some gray and now some orange seeping in. It's just so cool!!!! I'll try and get some pics. The Orange is mainly at the base of his mane, but I'm thinking it'll get darker. SO EXCITED. Question also, does this coat and mane change mean he's not exactly FULL palomino???? Just wondering.
I have a grey appy with varnish marks who goes from looking almost completely white in the winter to a much darker grey in the summer for show season and I have a red roan mini who is almost completely solid in the winter but has an amazing summer coat I don't have pictures on my computer of the two extremes or I would post them.