Mention of an HTC smartphone for Sprint, the HTC A9292, that apparently packs WiMAX had us scratching our heads earlier in the month, but according to Engadget it does have potential. Their "trusted source" has been spilling some details about the handset - apparently codenamed Supersonic - which will supposedly run Android 2.1 with HTC Sense and have a 4.3-inch display in a "svelte shell".
That display isn't an AMOLED panel, so we're presuming LCD TFT rather than anything more unusual like mirasol. The prototype apparently ran around as fast as you'd expect a Qualcomm Snapdragon-based device - such as the Nexus One - to run, but the tipster had no definitive chipset information.
As for physical design, the prototype had a flip-out kickstand on the back and was in white; obviously there's no word on what final colors and finishes might be available. There's apparently plenty of work still to be done on the currently-buggy software stack, which points to a launch later rather than sooner.