I know that if you really wanted to be rolling in the dough, you'd go get a MBA and a really nice office job. However, if you're willing to make ~20k/year and work your a$$ off I don't see why you can't make this happen. Let's just do some rough figures...some of which I'm pulling out of thin air (or a less pleasant place).
Cost per 11 gallon batch: $25 (this could be less or more depending on your supplier, power bill, or recipe)
Cost per gallon: $2.27
Cost per 6-pack: $1.28
Cost per 12oz. bottle: $0.2136 + cost of bottles (help here for cost)
Cost per 5g cylinder: $11.36 + cleaning/sanitizing (help here for cost)
Maximum batches per 10 hour day: 4 (5 hours per double batch from setup->cleanup)
Average batches per day: 2 (different recipes, back to back)
Price to customer
6-pack: $4.99 (remember the early SN days anyone?) = $0.8317 per bottle
5g Cylinder: $38 (equiv cost compared to multiple 6-packs would be $44.35)
Margin
6-pack: $3.72
5g Cylinder: $26.64
So for arguments sake, let's just assume you can sell every bit of what you make, and you make one batch per day. This of course is WAY less than how much you could brew, but let's just start there:
11g = 1408 ounces = 117.33 bottles = 19.55 6-packs
OR 2.2 cylinders
If you sold it all you'd make:
19.55 - 6-packs @ $4.99 each: $97.55
OR
2.2 - 5g cylinders @ $38 each: $76.00
And your profit would be:
6-packs: $72.55
OR
Cylinders: $51.00
If you spent 8 hours/day working making one batch of beer, ordering supplies, making phone calls, cleaning the brewery, making deliveries, cleaning bottles/kegs, bottling and kegging:
Your hourly wage would be between $6.38 - $9.07 per hour.
Keep in mind none of these calculations include health insurance, taxes, business and alcohol licensing, health inspections, fire inspections, broken equipment, stupid customers that want a refund for no good reason, bad batches that you have to throw out, etc. If I didn't have a family, I would think about it seriously even at that low wage. Even in Chico, where SN would tower above me like a Dubai hotel. I love brewing, but I have to earn a decent wage to provide for my family, and making good money just isn't going to happen quickly if at all. I'd plan to not be profitable for 2-5 years, and be working my tail off from 7am to 7pm every day of the week. And most nights would be spend visiting local bars, restaurants and keg parties to promote my goods. Sounds like fun, but I'd only do it if I were a single guy with nobody to worry about but myself.