You might want to look over this site http://www.beertown.org/craftbrewing/about.html
It is the home of the Brewers Association. They have LOTS of information about the craft brewing industry. Send them an E-mail and tell them your plans. They should be able to suggest more information for you.
Look through all the links, read the statistics and join the BA. Get the Brewers Resource Directory.
Contact the turn-key brewery suppliers. They may have some used equipment on hand they may be willing to sell.
A lot of the early brew-pubs and micros started out with used dairy tanks.
You really don't want to use ANY equipment that is not stainless.
You are correct in thinking THE MOST IMPORTANT thing in the brewing BUISNESS is marketing. If no one buys the beer, it doesn't matter how good it is. You should contact a distributor to see what sort of "product" they might be able to sell. In some states a brewery is NOT allowed to self distribute.
Here is another link http://www.beerinsights.com/
This is for a trade publication called beer marketeers insights. It should give you a better idea of what sort of challenges you might face.
When I was hired to open the Hubcap Brewery and Kitchen in Vail, CO in 1991, the entire build out of the brewery and restaurant was about $350,000. that was with a 7 bbl, steam fired, two vessel, brewhouse, three 7 bbl open fermentors (they had lids, they just weren't pressure vessels) and 12 used Grundy tanks (British pressure vessels adapted for serving).
The SandLot Brewery at Coors Field was built as a pure brewery. 10 bbl three vessel, steam brewhouse (mash mixer, Lauter tun, Kettle) with four 20 bbl cylindro-conical fermenters, four 20 bbl aging tanks, and eight serving tanks. Coors was paying the bills. The budget was $500,000. We spent $800,000.00 before opening day. I made a few mods to the gear and probably spent an additional $50,000 in upgrades during the first year.
The last place I was involved with was the RockYard Brewing Co. Another pub. Budget was $250,000 each for the Brewhouse equipment and kitchen equipment. Both came in over budget.
It typically takes 2-3 years of operation before a business venture will show a good profit. In budgeting start-up costs, you should also figure in operating capital to keep you going during the months when you are running at a loss.