In a Vacuum about Vacuum's

I have dreamed up what might be the ultimate Homesteading Implement, enough so that I might even patent my design, but ideally it needs a vacuum. I have worked with industrial sized vacuums when I worked for the railroad, so I know how to set one up, but I do not know how to size one. When I go to look up vaccum design principals up on the internet, all it gives me is residential vaccums.

Does anyone know anything about vaccums?

I would like a moderate vaccum over a 6 inch, by 48 inch rectangular space, going into a 4 inch tube, with a vertical height of 4 feet, in a 10 foot length. The vaccum itself can be any design, but I am limited to 25 horsepower for a power source. Is that possible?

I don't know anything about this, but... a 120V central vac would have around 3HP available on a 20A breaker, and is likely using a 2" hose from the wall.

Your 'nozzle' would be 72x as large as a 2x2 square... you have around 8x the power available...

Doesn't sound great at a casual and uninformed glance...

A few years ago I would have known the math but I flushed that to make room for permaculture  

How many inches of water vacuum do you want across the 6x48" space?  Does it have to be fairly consistent across that area?  Am I following correctly that the suction head (6x48) would be attached to a 10' long 4" dia tube that rises 4' from one end to the other?

If so, the first thing to consider is that air really likes the path of least resistance.  So if you just make a 6" by 6" by 48" box and hook a hose up to the middle, the vacuum right near the tube will be tremendously greater than the vacuum 24" away at the end of the box.

To get the vacuum somewhat even you'd likely need to have a long transition from 4" to 48" so the air travels the same distance.  In reality, the obstruction to its travel needs to be the same but by saying distance it will hopefully resonate.

If you're crafty, you could block off the vacuum where it enters the box too easily by covering that portion of the box with a perforated screen.  Fewer perforations where the vacuum is higher, more where it's lower.  

A 25hp industrial vacuum fan can really suck some air.  So I think it's possible depending on how you want the vacuum to really work.

Vertical height with vacuuming air isn't really a concern (compared to lifting water with a pump).