Rather than ask for a higher credit limit, ask if you are able to exceed the limit. If the account is new they may say no, but if the account is well established the answer will probably be yes, but not with a numerical answer.
Thanks for the tip. I'm interested increasing my MS activities on this card but am limited with a $7k credit limit. I'm trying to figure out what is least likely to lead to a shutdown - cycling the credit limit or exceeding the limit. Seems like both are bad ideas.