I haven't done it myself, but I understand it's a couple of hours work if you've never done it before. Probably minutes to an hour if you've done it before, and less if you have it scripted, but I don't think many people do. Note that I'm not saying that Ripple Labs doesn't have closed source code, but that's just like Bitstamp or Mt Gox or blockchain.info having closed source too. The essentials like client and server and lots of supporting stuff as well are open source.