I've been thinking about Meziere'* electric water pump. Does the belt run on an idler pulley in the original position, or does it avoid the water pump all together?

It avoids the wp all together.
Not sure how it looks on a series 1 but heres how it looks on mine:

It avoids the waper pump all together...

Ok, how does it route on an L67? We have 2 belts.

It routes fine on a series 2 L67. If I had a series 1 I would be able to tell you how and if the belt could be routed.

But only one belt runs the water pump. So the other belt would be ran the same.

Yeah..if you omit the pump, you go from crank to AC to alt... I'd bet it'* a piece of cake.

That'* going to be quite interesting on a Series 1, since the SC/AC/WP run off one belt. AC delete with a shorter belt is possible, but I'm not sure about bypassing the WP.

What benefits come from converting the water pump to electric? I mean even if you're removing that much more work from the pulley system, aren't you just making your alterator work harder and losing whatever gain you get anyway?

The electric pump shouldn't pull that much power. And the premise is a two fold I believe. First the pump runs at a constant speed regardless of engine rpm and you remove another pulley and power drain on the engine.