Some manufacturers come to mind WAC lighting http://www.waclighting.com/USA/ You should be able to find entire solutions at either your local lighting store or online For example http://www.pegasuslighting.com/3inch-12v-mr16-halogen-recessed-lighting-housings.html The only thing small about 3" lighting is the aperture. There is quite a bit of stuff (housing, power supply) that gets stored above the ceiling.

The human eye is not capable of distinguishing the difference between 2700 & 3000degK The Kelvin luminance scale was originated for the photography industry to indicated the white balance of photographic film. Try a personal experiment..On a bright sunny day look out your window at a white object then look at a white object in the room under incandescent lighting. You will notice that the incandescent light emits a slight yellowish cast. Now if you come back at night when its dark that same white object under the incandecent light will appear white and you won't notice the yellowish color of the light. That is because you eye has automatically compensated for the color balance of the light source. In the photography business they were sometimes shooting outdoors under natural daylight, while other times they were shooting in a studio with incandescent lights, but if they used the outdoor film indoors the photos all came out with a yellowish cast. It would be easy to make film dyes that would reproduce white under nearly any lighting condition, but they needed a standard so the film manufacturer could inform the photographer what type of film it was. To create a standard they put a piece of pure carbon in a lab furnace and began heating it. It started out coal black, but as it was heated it began to glow, first a dull yellow, then a yellowish red, to a bright red to a reddish blue, then to a blue like the gas flame on a stove, and on until it was a pure white matching daylight white. They recorded the temperatures as the colors changed and they determined that the glow from the carbon matched incandescent light at 3200 to 3400 degrees Kelvin and the bluish white light of daylight was at 5500 to 6000 deg kelvin. Although there are dozens of special films for photography, basically the two that most consumers are familiar with are indoor film (32K) and outdoor film (64K). If you have a digital camera it probably has a White balance control. Try an experiment for yourself. Set your cameras white balance to incandescent and shoot a couple pictures indoors, then switch flourescent and shoot the same pictures again, then switch to daylight and once again shoot the same pictures and you will see the difference in color balance. Up until the late 90's primarily all we used for indoor lighting was incandescent so there was not much emphasis of telling you the color temp of the lights. Some incandescent and flourescent lights have an internal coating on the glass envelope and the lamps were listed as daylight balanced, but nobody paid much attention to that. With the advent of the mini flourescents and LED lights we are seeing some rather radical color shifts so now the industry is labelling the lamps with the Kelvin Luminance number....Basically the hotter the Kelvin number the whiter the light output will be.

People tend to like a "warmer" color in the home, which is why I think most people tend to go with 2700K. The "washed out" look might be due to the color being cooler. I don't think you can go wrong with the 2700K, as that's also the same color temperature (incandescent) of most CFLs.

Here's a shot of our kitchen. The recessed cans are MR16 50W Halogen. They have a color temperature of about 3000 degrees. The undercab lights are LED and have a color temp of about 6500 degrees which is why they appear to be much more blue. Probably too blue for most. We like the look of the higher color temp with our cabs, backsplash and countertop. It also feels like the light is much brighter. Just as a point of reference, incandescent lamps have a color temp of about 2600K. Halogen is about 3000K The difference of a few hundred degrees of color temp won't be all that noticable unless the lamps are next to each other. I would, though, consider what effect the 2700K lamps will have on your white marble countertops.