Heads up, I added my newly-RNGd, near-perfect Timid Shiny Thundurus with HP Ice. (: If you're interested in making an offer, feel free to post in my thread! Also, there's Shiny Landorus too if you want, but I know you were seeking specifically a Shiny Thundurus.
I managed to RNG myself a Naive Shiny Tornadus, so that means that I can move on and RNG Shiny Thundurus now! lol I've been spending so much time on Black and finally somehow RNGd myself the genie... so annoying to do it. I spent literal days on this ugh. Just letting you know! However, if someone offers a Shiny Thundurus to you before I can, don't hesitate to take the offer, aha.