Soundbrew makes some good points about the cost of production vs the cost of buying craft beer at market prices.
If you can make fantastic beer, better than what others are making, and you can sell it for a substantial premium over other's prices, and you're good at marketing and open your brewery in the right market, you might be successful with a small system. But there are a lot of great breweries, and chances are slim that out-of-the-gate you'll make better beer than they do, and even if you do, you might not be able to convince people to pay more for your product.
If I were beer saavy, without a lot of money, and wanted to open a beer-business, I would open a small bar in a good location with a very good selection of rare/great beers on tap or in bottles.
There is a brewery not far from me that started off with a 10 gallon system. Yes, 10 GALLONS. They're still in business, and upgrading to a 10bbl system with a canning line. No idea about how/where they got the money for that. So if you're going to start small, start so small that you'll have no overhead. With no overhead, it shouldn't be hard to turn a profit.