hmm, could be much less than 6 six months, who knows? I just say that because I want to have some space inbetween projects, and my next project isn't going to be for WC3. If I decide to do a fourth campaign it will be for SC2.
Also, I got an internship as a level designer within a german company, so I'm doing this professionally for the next couple months. I'm not sure how that is going to affect my mood on doing additional work on a hobby-project like TLG...