The upcoming quad-core smartphone currently codenamed HTC Endeavor has already gone through one identity change, starting out life as the Edge — and long rumored to come to market as the HTC Supreme. Well HTC may still use the Supreme branding for another phone — possibly the sleek dual-core Ville — but we’re now hearing that Endeavor will go by the name HTC One X when it’s introduced at the end of the month at Barcelona’s Mobile World Congress. Apparently the “X” will be placed as superscript above the word “One” for branding purposes.

An HTC subcontractor has already reserved the Danish URL htc-one-x.dk, presumably for use as a future microsite.

What’s interesting about the name, part of which HTC trademarked in Europe late last year, is that there was once a rather striking concept phone dubbed the HTC One. That handset was highlighted by nearly edge-to-edge glass as well as a unique hinged body which allowed it to fuction as an alarm clock when placed on a surface in landscape orientation.

This version of the One, as we now know, should feature a quad-core Tegra 3 processor, 4.7-inch HD display, and point-and-shoot-like eight-megapixel camera. Leaked ROMs have confirmed a Sense 4.0 build running atop Android 4.0 Ice Cream Sandwich.

Update: Interestingly, Slashgear is reporting that the Ville will be given the similar-sounding “HTC One S” branding, following what must have been a successful experiment with the Sensation, Sensation XE, and Sensation XL.