TheBrewingNetwork has a show on nano-breweries that you should definitely listen to if you're serious.
My first response, however, is that 40 gallons is far too small a fermenter to make your plan work. You'll have to pay a fortune in licensing fees to both the federal and state regulatory commissions, and you'll have to comply with both state and local health regulations (which means money on equipment, space, testing, etc.) 40 gallons, moreover, isn't even enough to keep a single bar supplied for a month.
I just don't see a way to recoup your costs. I'd definitely push for you to take Colonel Forbin's suggestion and get started working in a brewery for a while first, even if only to discover all the hidden costs involved before you make the plunge.