Sivka-burka was brown, red and white in the same time. But as i see you may be read a different version where Sivka was silver-golden. Anyway i like the picture. Not every day we can see such characters around^^
Actually, I haven't found any versions where his colour was described properly. The closest I ever got was translating his name as something along the lines of 'warm(coloured)-grey / chestnut.' Most of the lacquer-work I've found with him on it had him golden with an orange mane and tail, which didn't make sense at all, save from a cool-coloured magic horse stance. So I've done him as a glittered-up red-roan, which was the best I could do to stay true to his name and the lacquer-work. Actually, if the red, white and brown is right, then I'm not doing too badly, since that isn't a bad description of red-roan! = )
Not sure about roan. You see, some things may be lost in translation. "Sivka-burka veschaya kaurka" at least as i think, may be a mix of "siviy" (horse will got such colouring: [link] It's more colour of milk then grey),"buriy" ([link]) and "kauriy" ([link] that can be mistaken for red).
Бурый isn't greyish-brown. бурый = dark-brown. Like this one: [link] or this one: [link] And каурый usually described as reddish,whose mane and tale are reddish-brown (darker then body), legs are coloured even more intensive then rest of body. Also it got a red "belt" on it's back. So i'd say that such horse must remind a Prezhevalsky horse but with brighter coat. Alive Sivka could look like this horse but a bit more reddish: [link]).jpg