5000k is considered sunlight (although your also correct that it is shifted slightly blue as you move away from the equator). A 6500k bulb would do just fine. Equally important as color is intensity. Particularly for VFT and other full sun loving plants! You would need several of the tube fixtures placed a few inches from the plants. Better yet would be some sort of high intensity lighting such as metal halide or sodium or high output fluorescent. You could also go for the high wattage compact fluorescent.
They make 65watt 6500k compact fluorescent bulbs that screw into a standard light fixture. Or you could try the outdoor security light by Fluorex or Regent available at homedepot and lowes. These use a 65watt 6500k compact fluorescent bulb also.
My opinion on the incandescent plant bulbs.. totally worthless. ALL incandesent bulbs produce a huge amount of red and infrared light ie HEAT. Getting the plants close enough to the bulb so they receive the proper intensity results in crispy plants. Move the bulb further away to keep the plants from frying and they don't get enough light.