Bukkit

Summary of the posts:
http://dev.bukkit.org/server-mods/spoutessentials/?page=2#c197
http://dev.bukkit.org/server-mods/spoutessentials/?page=2#c193

In Overlapping WorldGuard-regions with defined priorities the outer texture pack is overwriting all inner texture packs.
I.e. the city's texture pack is DokuCraft_Light, the palace texture pack is DokuCraft_High. But DokuCraft_Light overwrites all inner settings.

In the pastedbinned config below its minecadia (whole city, default texture pack), minecadia_uppertown (DokuCraft_High) and minecadia_lowertown (DokuCraft_Dark).
The region cloudcity_radiance is not overlapping with cloudcity (DokuCraft_High) , but is below Cloud City, so that the texture resets to the default DokuCraft_Light (see Ticket 107).
Cloud City is working fine. The two Minecadia-regions are not working at all, as they copy Minecadias texture pack (default, which is DokuCraft_Light or whatever I define for the minecadia-region).

To the priorities:
Priorities are numbers (negatives are possible) assigned to a region to determine its rank. A higher number is a higher priority.
Source:
http://wiki.sk89q.com/wiki/WorldGuard/Regions/Introduction#Priorities

Configuration:
http://pastebin.com/MyAKF8a4 -- config.yml
http://pastebin.com/4G8Jj7if -- modules.yml
http://pastebin.com/z8Mjhcu7 -- World Guard regions
((The priorities are delicately set and perfectly working. This is just a short example, Minecadia and Cloud City are containing each about a dozen subregions. For example an arena area where priorities are important because the spawn-protection and the explosion-protection have to be disabled, which only works with correctly set priorities. Without priorities Minecadia's "deny" would overwrite all "allow"s of all sub-regions.))

As a picture does say more than thousand words here pictures of the two cities (loading takes a while):
Minecadia: http://minecraft.scaenicus.net/dynmap/?worldname=wrld_creation&mapname=flat&zoom=4&x=16.5&y=64&z=737.5
Cloud City: http://minecraft.scaenicus.net/dynmap/?worldname=wrld_creation&mapname=flat&zoom=5&x=-112.5&y=64&z=352

SpoutEssentials 3.7.5
Spout build 510
CraftBukkit Build #1337

Added the region-definition as this might be of an interest.

Sadly, WorldGuard's own region manager isn't very good atm, so for now there are no priorities :(. My plugin will simply get the texture pack for the region that the players touches first.

It's not the solution I hoped for, but actually that helps. Thank you!

Should I nudge sk89q to update the region manager, or are you already on it?

Edit: Another idea: Would it work to use the "parent" value? Child-regions copy from parent regions but overwrite the texture-pack of parents if any is set in the child-region.

@skawke: Go Priorities should work now as of the reference-sheet

Source: http://dev.bukkit.org/server-mods/worldguard/

Updated Links to Servermap... any news on Texture Packs with overlapping regions?