I'm also sleepless in Seattle. Or Jobless in Jobland. 6 years international experience and one of those mainstream English teachers. Am I doomed? :)

I think it largely depends on the individual school. I jumped around to a few of the international schools in Tokyo and for each one was put on a local hire contract. For each of these it meant no housing or flights, but children's tuition was covered.
Unfortunately, some schools love local hires because of the ease and cheap nature. There's one or two in Tokyo notorious for this and unfortunately don't seem to care much about qualifications or experience, but seem to hire with saving a buck in their thoughts. These schools will hopefully realize soon that it's in their detriment to do this.
Japan is an awesome place though, and if you can enter on a foreign hire package (or a good enough local one), I'd say go for it!

Having done this myself, most of the international schools in Tokyo will treat you as a local if you are already set up here. I do know some schools that will give minimal benefits to local expats, but nothing as good as the international hires.
I would wait for the fair and try finding an international package.