More Speculation on a White iPod Touch

"We’ve been rambling on about white iPod touches for awhile now.   Back in June we postulated that Apple would create a white iPod touch after successive launches of white iPhone and iPad and launched a survey (over 80% of you wanted that guy above)."

As we've seen with demand for a white iPhone, potential buyers are clamoring for a white iPod Touch. Several sources have written that it's on its way, and opine that the only changes will be color, an oleophobic coating on the display, and a better ambient light sensor. Apparently users hoping for a better camera are going to be disappointed. Wouldn't it make sense to build only one device (okay, with two colors) that is an iPod and an iPhone, with the ability to "turn on/off" phone features? Is there a significant cost bump adding 3G / 4G phone features? Just wondering.