The difference is indeed pronounced, but here are some excellent distance running schools on the East Coast as well. Here are a few that come to mind:
In recent years, some of the Princeton and Columbia teams have been quite good, though they tend to be stronger in track than in cross country. NC State and Virginia have had some very good teams and individual runners, though Virginia might not be quite the same program (track-wise) with the departure of Jason Vigilante. Villanova, Penn State, and Syracuse typically put together excellent teams in both track and XC. Arkansas was a powerhouse in XC and track for many years, though I'm not really sure what the state of affairs is these days. I know Georgetown has an excellent women's program, but I'm not sure if their men are anywhere near as good. FSU has had some distance standouts over the years, though I think it's much stronger as a track program. And every now and then, Harvard will have one or two standouts.
Hopefully that isn't too much noise in the equation, but some places worth looking into.