Lasfit makes color changing bulbs (you change the color by cycling the power to them) where one of the colors is 'amber', 4300k. they're the '4-mode' version here:
3000K yellow light penetrates active safety protection to prevent accidents by increasing overall visibility and road illumination in harsh weather. 6000K white light increased visual field and distance visibility in darkness weather.
www.lasfit.com
I picked up the 2-mode ones because I didn't care about amber or the 'sos' thing, and they're extremely bright, very happy with them. A bit pricey is the only real drawback - well, that and you'd have to hit your fog light button 4x to get to 'Amber' from white, which is where they start, i think.