If I remember the patch for Extra large maps comes originally with WoG H3map editor. Extra large maps: imported (added in v0.5.0) Maximum map size is now 256M tiles, ranging from 16k x 16k to 256 x 1M. (The NewGRF debug inspection window is disabled for all map coordinates longer than 27 bits). Download a complete compiled version of OpenTTD inclusive this and other patches (close&update airports) and GRFs here. NOTICE2: 4 GRFs installed => DB Set v0.82 (XL), NewStations v0.42, PlaneSet and GermanTramSet. You should be able to play the scenario without these.
Main / Personalization / Heroes 3 in the wake of gods maps OpenTTD Joker (JGR) Patch Pack Multiplayer Servers (self.openttd).
Heroes 3 Maps - In the Wake of Gods + Era. The Biggest collection Maps for Heroes of Might and Magic 4(IV), Heroes 5(V) and Heroes 3(III). Random Maps download - novinky zo sveta Heroes 3, Heroes 5 a Heroes 7.