AR9mm,
You can most definitely get an FFL at a home business. Here is what may confuse some:
1) You must have a seperate, locked storage container for firearms you are selling, as opposed to personal firearms. These firearms must be in different rooms. This container can be a safe, a gun cabinet, etc.
2) You must have hours of business, where your business is actually open to the public. This is simple. You can do one of two things. One, you can be open for 10 minutes a day. Obviously, noone is going to show up at your house if you don't have signs posted and whatnot (which would violate zoning anyway).
If you meet these two things, which are easy, you can get an FFL. Read up on it and you'll be surprised at how easy and possible it is to get one. It takes a few months for the BATF to process it, but other than that, you're good to go.