Problem with that is that it could never stand up to the explosion created in the combustion chamber, thats why valves have been the same for 100 years. The valves push down to open and pull shut upwards, when combustion happens it also forces agaist the valves and helps close them. Another idea was to use a butterfly valve in place of a std. valve in the heads, but the same problem, the combustion would ether blow the valve open, or just explode it right up into the head. Plus you cant have a butteryfly valve cause the combustion would blow out the seal on the butterfly rod.
Ideas... Ideas... Ideas.... Keep thinking!