We'd already had some indication that both the HTC Mondrian and Mozart would be Windows Phone 7 handsets, and it looks like that has now been all but confirmed by HTC itself. According to some XML files dug up on HTC's own site by Conflipper, both devices list Internet Explorer Mobile 7 for the browser ID, which we can only assume won't be making an appearance outside of Windows Phone 7 anytime soon. The files also confirm that each device will have a 800 x 480 display and a keyboard-less form factor, plus A2DP Bluetooth support, although there's expectedly few details to be found beyond that.