I have struggled for years to "get" the hybrid bike thing. One of the things that I don't understand is what the difference between the wheels that would be found on a hybrid bike, a cyclocross bike and a 29er. Clearly I'm talking about "stock" wheels not specialty ones.

Many or most hybrids have 135mm rear spacing, which is near standard for MTBs and touring bikes as well. The resulting reduced dish favors a more durable wheel, but this is probably unnecessary for the unloaded, recreational pavement jaunts.

I believe most cyclocross bikes, particularly the competitive models, have 130mm spacing. Wheels for cross bikes seem to be very much like a sturdy road wheel build (32h x2/x3) with similar rims.

Rim width is all over the place.

I think 29r's tend to have a rim a "few" mm wider than a hybrid.
My Globe had 23mm rims. I built a set of wheels using Sun Rims M13 II's and use 26mm tires.
Does that make it a flat bar road bike?