Got cards couple days ago; I filed my case by myself and learnt a lot from this forum during the past few years. Always want to give some feedbacks. Here are some, just from my personal experience, probably not be useful for everyone.
1. Case re-link is possible. I got both EB1 (TSC) and EB2 (NSC, RD 02/2007) approved, original 485 with EB2 (RD 11/2007), wrote to NSC asking case re-link and got a letter from NSC showing they received the request, case was approved and cards were received within 2 months.
2. I also submitted a new 485 to TSC, case was accepted without any charge (NO APPLICATION FEE), and they gave me a new case number. It is still pending, though.
3. The customer services in the national service center know nothing! But if they can transfer you to an IO and who happens to be nice, then it really works! It is worthwhile to try.
Good luck for everyone.