Summarizing most of what's already been written into a single post:
1) There is conventional butter and pasture butter.
For the highest vitamin K2 content, the butter must be from cows fed grass in pasture. Silage and cut hay does not have the high K2 content that fresh, green feed butter has. Conventional butter from corn-fed cows is going to have very little K2 and an overall lipid profile likely higher in O6 and lower in O3 as well.
One can buy pasture butter specifically, or buy butter from a small, local source in season, or make it oneself from cream from a small, local dairy in season. Note, butter will keep well in a freezer.
2) There is butter, clarified butter/ghee, and "high vitamin butter oil".
Butter is fat precipitated from milk.
Further processing can yield clarified butter/ghee, which is butter that has been rendered to remove residual water and milk solids. Clarified butter is purely fat and fat soluble vitamins.
Still more processing can yield high vitamin butter oil (HVBO). HVBO was originally described by Weston Price, and today seems to be a product produced exclusively by Green Pastures. GP uses a patent pending process to produce their HVBO (yes, a patent medicine). The key differentiator between butter oil and clarified butter is separating (by centrifuge or decanting) the vitamin rich lipid layer from the rest of the butter "wax".
3) Obviously clarified butter can be made from any type of butter. Just as there are manufacturers that specifically sell pasture butter, there are manufacturers that sell pasture clarified butter. HVBO is inherently from pasture butter.
4) The last remaining issue is how concentrated is the GP HVBO? GP HVBO is rather expensive, $58 for a 1/2 lb jar. Depending on one's source, 8-12 lbs of unrefined butter could be purchased for the same sum of money. GP on their web site and in their patent application does not report the yield or concentration of butter oil from unrefined butter. Commenters on other threads at PaleoHacks and elsewhere on the internet have mentioned a 1:8 ratio of HVBO from butter. No one has cited a source however. GP may be treating this info as a trade secret.
5) As most Paleo folks are on a low carb, high fat diet anyway, for my money I'd simply eat pasture butter stockpiled from spring production or maybe try one of the pastured ghee products. However, for picky children, folks not on a high fat diet and those struggling with some chronic health conditions, eating 10 times the butter may be impractical.
I hope I've straightened it all out for folks. Feel free to comment if I've made a mistake or missed anything.