Microsoft CEO Steve Ballmer had plenty of good news to share with the company's partners during his keynote speech at the annual Worldwide Partner Conference (WPC) yesterday, such as Windows 7 selling 400 million licenses in under two years, or Office 2010 selling more than 100 million licenses in the same amount of time. When it came to Windows Phone 7, though, he admitted that sales have "gone from very small to very small."

That isn't stopping the company from drumming up interest in its upcoming "Mango" update, though. In fact, Microsoft did a little more than that and actually gave a quick preview at a handful of unreleased and unnamed Mango-powered devices from Acer, ZTE, Fujitsu, and Samsung. Sadly, the company stopped short of sharing any specifications, but Samsung's unit sure garnered a bit of interest for its obvious resemblance to the Galaxy S II.

Steve Guggenheimer, corporate vice president of the OEM division, specifically described it as "the new Samsung that's coming," noting that it's very thin and light. Microsoft later clarified that these phones are not production devices and may not be indicative of their upcoming handsets -- though we'd be surprised if a Mango-powered S II is not in the cards.

Guggenheimer also said that future Microsoft handsets will feature "thin and light" designs with "phenomenal screens" and "great battery life". You can watch the video of the keynote here; the phones appear around the 2:19:40 mark.