Sure, if you don't mind waiting for things to happen.
Remember the iMac range is primarily aimed at consumers who want something that looks pretty, is well built and takes up a small amount of space. It does those things very well, but at the expense of performance, expandability and functionality.
If your processing large numbers of RAW files from a 5D2 and a 7D then you do not fit into Apples target market for the iMac.
Your either going to have to cope with compromises (big screen to get the performance, or small screen but no performance) or your going to have look at other alternatives.