Single foster parents - How many kids?

Is there anyone here who is a single foster parent AND works full-time (either running a business/telecommuting or working outside the home)? How many foster kids do you have/feel comfortable having? I'm not a foster parent, but I want to become one down the road, maybe 5-7 years. I'm trying to start my own business and save for a house, so it'll be awhile. Anyway, I've always wanted to have a big family, so I'm just curious as to what you single foster parents feel is "doable".