I think this is a pro option.
Did anybody already get to use that?

i tryed this awhile back in commerical , on a wave model , it reacted to it but not the way i wanted, it just pushed it to one side.

But how can I implement it?

I'd like to have water waves that will push my canoes along a stream. I've thought of the conveyor blocks in the Newton demo as a way to accomplish this. Maybe the Conveyor forces can be combined with the buoyancy demo and the wave action water shader.

Ideally the canoe paddle would react with friction against the water too, and propel the canoe...

Any ideas on how to do this?

I've seen many threads asking for boats enabled. Maybe a group of us could put it together.

Use ent_vertex to warp the verticies of a water model when the player passes near them. I don't know how you would script this but it's an idea.

Try the demos of Ogre3D , one of them
is about waves made by an ogre head moving along a water plane.
you can look at their code, ogre 3D is open source.