Based on OpenTTD 0.3.0 and thus also released under the GPL (see LICENSE.TXT).
Extract into working ottd 0.3.0 directory to play.
Features:
- 1024*1024 mapsize
- save game extension .bsv for big maps
- For cargo payment rates transit days count 1/4th
- large map window size + 50%
- generating land in scenario editor also generates towns/industries
- planes maximum speed times 4 with slow acceleration
- high towns/industries settings produce really large amounts of towns/industries
- towns less likely to build fountains / statues... nothing to do with bigger maps but I just hate statue towns =]
- ai starting immediately means they start IMMEDIATELY. (I implemented this for testing, but I quite like it as a feature)
Bugfixes:
Fixed: Town names were double (it crashed sometimes when you click them)
Fixed: lower land option didn't work well ('it's already at sea-level', 'too close to the edge of the map', both not true)
Fixed: When creating a scenario it didn't save/load well.
Fixed: raise large land over edge bug
Fixed: some towns had 0 inhabitants
Fixed: desert map generation crash
Fixed: scroll bug: fast scrolling on maximum zoom out
Fixed: tileloop was too slow, now sped up to normal
Avoided: ai bug: buildtrackrecursive crashes / turned off ai train building
fixing this will mean a complete rewrite of the ai, which will be necessary anyways, but by the time that's done bigger maps will be in the official release

I realise that this now permanently cripples the ai, but it couldn't handle the big maps anyway...
Not fixed: scroll bug - wrap around from extreme left tip to extreme right... No idea what causes this. Doesn't do any real harm.
Remarks:
- incompatible with small map savegames.
- incompatible with 0.3.0 bigmap savegames
- save games are ~ 1 Mb in size even when using zlib.
- map generation will take longer with industries or towns set to high.
- the sorting in the town list is turned off, qsort didn't work properly, I'm still looking into this.
- Any bugs that are part of Openttd 0.3.0 are part of the bigger maps version, please check if any found bugs aren't already posted on the sourceforge bug tracker.
Any bugs that were not reported for 0.3.0 can be posted at the Ottd forums at http://www.tt-forums.net/viewforum.php?f=29 in the bigger maps thread. (which is this thread)
have fun

Bigger maps 0.3.1 win32 executable + files
http://home.student.utwente.nl/m.j.a.pl ... igmaps.rar
Bigger maps 0.3.1 source
http://home.student.utwente.nl/m.j.a.pl ... source.rar
(You also need the files from the win32 rar)