I do this now.<p>I was doing client work, and to be frank, got tired of working from home and dealing with low-grade clients all day. So instead of worrying about finding better clients, I took a day job to support myself and my family (wife and kids) while I worked on side projects with my co-founder.<p>To date, we've built a fun iOS game, Santa Strike, a crowdfunding plugin for WordPress, IgnitionDeck, and a few yet to be launched iOS apps, among other simple software utilities like Iconswitch.me and GameDesignTemplate.com<p>I drive to and from work an hour a day, which kills me, but we're very close to being profitable enough so I can quit my day job.<p>We're not zillionaires yet, but I do think it's possible to do what you're asking. However, it's very very difficult, especially when you have a spouse and/or kids.<p>I work on my stuff from 7-8 am, drive to work, try to fend off the thought of being an unproductive employee so I don't get fired (I'm actually the only developer they have, and I'm in a very good position because my predecessors set the bar so very low), but do spend some time at work handling side-project stuff, get home at 6:30, hang out, work more, go to bed, rinse, repeat.<p>My wife is stressed because my mind is elsewhere, but she understands. We spend time on the weekends going out and doing family stuff, but not as much as we'd like.<p>When we ship new versions of software, I field customer inquiries and complaints on the go, which isn't ideal, but is what it is.<p>In other words, I have very little personal time, it's very stressful for the entire family, and it's a lot of hard work over a long period of time. It's not for the faint of heart.