To what end, Jeffrey? Going that far back, wouldn't it be better to review the information ancestor by ancestor, rather than simply rely on others?
Update: It looks to me like you can choose an ancestor, and not just yourself, for the gedcom download. So if you don't have too many lines going back that far, it should work to select ancestors in the lines you want to go further back in, and then download their gedcoms. (Please tell me if that works so I'll know for next time.)