I wonder if email and the internet make this any easier for kids nowadays? Patrick (who's nowhere near your level, but moved at least 9 times in 13 years and has been in 8 schools in 9 years) is still in touch at least sporadically with classmates he moved away from several years ago. It's not the same thing as being in contact, but it seems like it might makes thing a lot easier. Of course, he's also fairly extraverted, which helps hugely (as the article notes).

(I also moved a fair bit when I was quite young, but we stopped before I was old enough for it to matter much, I think. Plus I think having a twin very much insulated me, as I didn't have as much need for outside companionship when I was in grade school.)