@ rpgmakerxp08-
Sorry but what you are suggesting would not work. What your way would allow [though you've not really stated how to do anything] is as soon as the player "finishes" a game (ie, gets to the end of the story or designated point) he'll be shown a FAKE title menu, one in which an extra option, which would be shown by a picture, would allow teleporting to a new map.
The problem with this is of course, that as soon as the player turns off the game, that menu is gone, the fake screen will not show and the normal menu will return and will not display the "Extras" option.
To my knowledge something would have be made as a script. Though I think it would also edit the 'main' script as that deals with loading of all variables/switches/saved games...
BUT... and please don't ask me how to do this... I think I know a way in which it is possible.
When the game is complete, you'd need to set either a global variable (ie, it starts as 0 and you turn it to 1 when the game is complete) or a global switch to on as the game completes. Bare in mind, GLOBAL variables (or switches if they do exist in a global instance) do not get changed by event commands like the IN GAME switches do. Instead a line of script that changes them would be needed...
The title menu should be altered so that it has a conditional branch that gives something like the following:
IF: global variable "gamecomplete" = 1
Show:
New
Continue
Extras
End
Else:
New
Continue
End
End
Remember, im not a scripter but I could take a look at this at some point but dont expect it to be within the next two days...
I would suggest bumping this topic because, in theory, this should be quite easy to do with a little bit of knowledge.