Since your standalone includes the Max/MSP runtime, and the runtime is copyright Cycling '74, it's probably not actually kosher to completely remove their copyright notice.
That said, I think it should be all right to _modify_ the copyright notice to include your own copyright as long as your work credits Cycling '74 appropriately. I would re-read the Max User license to be sure, but that's your job.
On Mac OS standalones, the copyright string is included in the Bundle Info.plist file. The "copy rite" is: in the Finder, ctrl/right-click on the standalone, select "Show Package Contents", in the new window navigate to Contents/, double-click on Info.plist, edit away.
Don't forget that you can define your own startup screen as part of the standalone creation process. This may be more appropriate for what you want to do.