We're drowning in ultrabooks at this point, but we have a feeling the onslaught is just beginning. Our handy little secret Lenovo roadmap points to 13-inch "premium" and 14-inch "mainstream" ThinkPad ultrabooks coming in May or June of next year. Lenovo seems to be contrasting these ThinkPads with "consumer" IdeaPad U offerings (we just reviewed the U300s), and says "commercial" laptops that meet Intel's ultrabook spec will be running Intel's Chief River laptop platform, which will be powered by those fancy new Ivy Bridge 22nm chips. Lenovo is no stranger to incredibly thin ThinkPads, and its $1,300+ 13-incher will be a X1 (pictured) successor — the mainstream laptop will be closer to $800. Non-ultrabook ThinkPads should get Chief River in March or April. What's even more exciting is that Lenovo expects Windows 8 to be ready by fall of 2012 — Microsoft had hinted as much, but it's nice to hear a trusted partner spouting the same line.