I have seen a $30K limit of a BOA card. But the income was about $100K. But i'm sure the credit report was also clean with minimum debt.
I got in with BOA (after closing 3 of their cards in 2005 and put on a payment plan and had many lates back then). I was surprised they gave me $15K on the 1-2-3 Cash Privileges card.
I have also banked with them for a long time so that might have helped.