Meh, instead of a special map, the could just add a custom NPC to the DB rooms that would spawn the monsters when prompted.
"Wouldn't that be imbalancing" you may ask? Not at all. In order to spawn a monster the player would have to pay 100,000z which would then be transferred to my account.
People would have to weigh their love of 2.0 GD monsters and their drops against their disdain of the concept of making
me wealthy. Eventually these 2 conflicting motivations would reach equilibrium and they'd stop clicking. Or they'd run out of zenny. Whatever. Either way everybody wins
So start scripting that NPC asap