I've stayed at both of the Cairo Marriotts a few times. Unfortunately, I don't remember them offering too many "alternative" rates. But if I remember correctly, the rates they had weren't out of line with similar hotels in the same area.

I do believe I was able to work a corp rate with them given that I and a couple of my co-workers were traveling to the area and spending 3 weeks a stay there. And we were able to get a fairly decent discount that way.