There's a way to remove the "100%" that always shows up in the upkeep interface, exactly the way DotA hidden it.. Go to Game Interface, then find Text - General - Gold Income Rate. Type anything you want there, like a link to the thread of your map or it's forum (if it's a hosted project), after that, place this hex color code beside it:
|c22222222
That way, it can't be easily shown by players. It can, however, be seen in bright terrain such as snow but it's still almost unnoticeable to the naked eye.