I was at $5k before the fall...hit a skid Oct-Nov '06 with 4 30-day lates (BofA and Chase) and I think that's what did me in. No lates with AMEX... My utility's now <15%, but never more than 40. BofA did not renew me, even after I PIF'd on a $7,500 line. Wish I had known about the site then and would have gone for the recon.
Interesting note...I only asked for $1500 w/ AMEX (+ $1k), was approved, and went back in to see what would happen. Said I had to wait 30 (thirty) days (not 6 months) before I requested another CLI. I did PIF AMEX about a month ago...was determined I wasn't going to use a card with only $500 limit.