[PonyGumbo]

Yes, although it's not easily replicable. I spent a couple of years working remotely as a web grunt. Some weeks were insanely busy, but in general it only took a few hours a day of my time. I was able to do a lot of work on my startup between assignments. The key is to find the right kind of company. You want to be positioned as the technical asset who solves problems, not the person who creates the product being sold. If you're the latter (like a web developer in a marketing agency), then there probably won't be much downtime.