And I can tell you that there are many strategies that in "Custom mode" the levels are totaly random without blocks or parts of levels but for an RPG thiss will be harder to implement because of the quests and the events in the game. Thats why I suggested Diablo style...

PS.: I'm talking about RPG because the topic is 'Dungeons' and...I havent seen dungeons in other games than RPG and Advanture...