considering the way I operate my business as regards to pricing, no I most likely wouldn't.
when I give estimates and take on work I give the absolute lowest price that I can still turn the profit I need to make a living. I'm not in business to give my services away but I'm not in business to get rich either. so I personally don't mark up my prices crazy amounts or allow for any dickering of prices. my prices are what they are and if you don't like them your free to find someone else.
now likes others have said if the account made up a large chunk of my income I probably would consider it. notice I said consider. it still wouldn't be a drop in the bucket desicion for me.