Just wondering why OHC with roller followers need lubrication, if it's rolling contact everywhere? In theory, if we remove the valve guides from the equation, does an engine with OHC roller followers even need to have the top lubricated?

If it was still 1918, you might have a point.  However...

E.g., my Ford based Esslinger 2.0 that is in my 23 T revs to 9000 rpm and the little roller rockers really like that shot of lubricant! ;o)

Seriously, the cam gear, springs, valves(ball valve), lifters, rockers, etc. generate an enormous amt of heat and require a steady flow of oil for cooling and lubrication.

If there is no need for lubrication on a so called frictionless bearing, then why do they fail if they are not lubricated?  
There should then be no reason to pack wheel bearings with grease etc.
As a youngster I ran a 2 cycle gasoline engine without lubricating the bottem end, ie the crankcase, the piston had enough oil the way I was introducing the fuel, the big end with the needle bearings gave way.
The end answer is there is always friction, if not you could spin a perfectly balanced shaft with rollers and it should perform like its in orbit around the earth, with zero friction losses. Well I guess we need to get away from gravity too. In the end all friction less metal bearings need lubrication. I suppose ceramic do as well. 

MORE NEWS