Thanks for all your inputs! The large transaction on my business card is still listed as pending, and the FR rep (who was incredibly short and rude, even though I was so polite and understanding, and didn't even object to them shutting down my three cards) told me it would not go through until the FR was over.

I just faxed 26 pages of material to them today. Crossing my fingers!! I have had the same 20k limit on my AMEX Delta card since I was 18, and have never paid late, missed a payment and always pay 100% in full. If they decide to cut my credit, I almost feel like saying, "and you think my 24 year old employed self is less responsible with a 20k credit line than an 18 year old high school student?"