Idol X from Alcatel Is Less Than 7mm Thick
Alcatel showed off the Idol X this week in Berlin, an Android smartphone that measures just 6.9mm thick. The X may be thin, but it still features a 5-inch full HD display with Dragontail glass and a 1.5GHz quad-core processor with 2GB of RAM. The X also includes a 13-megapixel main camera and 2-megapixel user-facing camera that can each shoot 1080p HD video. Connectivity options include Wi-Fi, GPS, Bluetooth 4.0LE, FM radio, DLNA, and HD Voice. The Idol X supports UMTS 900/2100 and is unlikely to be sold in the U.S.
It's not thin enough
Also - if an iPod with a full hard-drive inside it can be 10.5mm thick, which is 3.5mm off, then 7mm is way, way too thick.
Thickness is the most irrelevant dimension
Even if the battery life is good it would always be better if that same tech was built into a bigger battery.
Of course when you are at a trade show a phone with an impossibly thin profile will be considered far more flashy and gather more attention than one actually far more suitable for the real world.