[Diesel_Dave]

I've worked with a couple prototype "camless" engines. Just google "variable valve timing" or "variable valve actuation" and you'll find lots of stuff. Various concepts have been around since at least the 70's, maybe even earlier. BMW (Valvetronic) , Ford, and pretty much all the manufacturers either have some limited form of this, or are at least looking into it. Some systems still have a cam, but have some additional mechanism of providing variable valve timing and/or lift.

The advantage of such system isn't the power consumption of the valvetrain. Frankly, I'd be suprised if there was one.

Here are some of the advantages of flexible valvetrains:

1) Variable timing can be used to eliminate throttling losses, i.e. at part load adjust your intake valve opening and/or closing time to get less air in the cylinder.
2) It enables you to run different valve profiles at different operating points so you can get the best performance everywhere rather than having to pick 1 profile that works okay everywhere.
3) It enables different cycles like Atkinson cyle or Miller cycle--even HCCI/PCCI combustion. Potentially you can also switch into or out of these cycles, although it's a controls challenge to abruptly change from one cycle to another with the engine running.
4) Cylinder deactivation is relatively easy.

People have also been looking at all kind of ther stuff. Like using it for "internal" EGR, i.e. close the exhast valve early to trap exhaust in the cylinder rather than sending it in a tube back around the engine.

The challenge with all this stuff is being able to control it effectively. Realize that with valves if you mess up for 1/10 of a second and valve meets piston = really, really bad things.