Miki Miyashita's Raisonne IV was a hard cover sequel to Raisonne III with new illustrations and a larger B5-sized format. Raisonne IV already really showcases how Miki Miyashita's style has grown, with better coloring and more proportional character designs. There's a mix of fan art and original works in the art book as well, ranging from Vocaloid to Code Geass.
Though Miki Miyashita has yet to have a commercial art book released, she's done more than enough work to have released multiple art book-sized doujinshi, and RAISONNE III is one of them. RAISONNE III was released during Comic Market 69 Winter 2005 and though it's a few years old, I only recently acquired it after being impressed by last year's illustration collection in RAISONNE IV.