I have the cool white bulbs in my garage of the toyhauler. I think they run in the 5K range, and I got them on eBay. I have the ones that are a direct replacement for the bulbs, with the round structure (not a panel) and a base that plugs in without an adapter.
I think they are just a little on the 'blue' side for my taste, but the color does clarify things when I am working back there. They are plenty bright, but they do give the area a more 'sterile' look.