Sourcing wheels for hybrid bike
Consider you are not finding what you are looking for for a reason.   

A larger tire does not necessarily have a lower rolling resistance.
A the same pressure a larger tire actually has a lower rolling resistance.  

Over city terrain I would take a 28 mm or 30 mm over a 23 mm for rolling resistance.  

For ride and flat resistance I would definitely take a 28 mm + over a smaller tire.  

Racers go with a narrow tires more for wind resistance. On a hybrid you don't have nearly the aerodynamics of a road bike - you are taller and wider.  What you pick up on a small tire on hybrid is just not worth it.  You already have the wider fork and rear hub.  Putting smaller tires on it is just not going to change the aerodynamics much - especially on the rear.    

I would stay in the right sizing for your rims and go with a low resistance road type tire. 

You probably have like a 20 mm that will take 28 mm tire fine.
If you are bigger than 20 mm you can find CX 135mm wheels as low as 20 mm.    

On the front you if you are dead set then you could find a road wheel for the front.
But I still don't think 23 mm is going to make you faster than a 28 mm on that bike.

If you really want speed then I would put that money into a road bike rather than a custom wheel build.