This pretty much describes exactly what I did. I worked on my idea nights and weekends for about 6 months (iOS app) before launching. 6 months after that I was profitable enough to quit my job and do it full time. Instead of going the typical startup route and seeking funding and hiring people, I decided to travel the world while building up my startup. After a year of doing this, I'm making many times what I was at my day job in silicon valley and really enjoying being my own boss. I think the army of one part-time idea really resonates with my personality. I like the idea of startups, but I have a family and am fairly risk averse.