Tiki,
Relax already. You've done enough. I remember on my medicine sub-I 4-5 months ago, I was on a team with a fresh MSIII. At the end of the rotation she had written thank you notes to all the attendings, residents, and interns on the rotation, and asked me if I wanted to sign them as well. I thought this was rather odd... and she told me that it was her understanding that everybody did this, and she had done it on every month of every rotation she had done up to that point. I told her it was really overkill, but that it wouldn't hurt her to do it if she really wanted (although I secretly thought it would hurt her since she would seem like a brown-noser). Oh, yeah, she also took pictures of the team and afterwards sent everyone the pictures.
Anyway, point is, I don't think it matters at all, and I bet at most of these places your spot on the ROL was dictated before they ever received your thank you note. I never sent a thank you note to any program. I also only sent e-mails when I had specific questions. After interviewing several hundered people, I bet most PDs get thank-you notes and e-mails and ask themselves "who the heck is this?" before bothering to look you up and your evaluations, to see whether or not it is worth wasting their time to write you back.
