You can find some maps large enough to serve as a mural on maps.com: http://www.maps.com/Search.aspx?q=mural

Here's a link to a place that does wall murals that, I believe, stick on and can be removed if desired.
http://www.muralsyourway.com/maps-flags-murals/

There are several places where you can find world map prints, but murals are definitely easier to install than wall paper since there is no need for glue or paste of any kind. We do carry a world map mural in our collection, here is the link to it:

http://www.dezignwithaz.com/world-wall-mural-p-1679.html

Hello,
this is not a room we designed, I put it in an idea book. You can ask the room designer that is list or try this site that someone else posted. http://www.dezignwithaz.com/world-wall-mural-p-1679.html
Good luck!

If anyone else is looking for really large wall maps, try http://www.mapsales.com/world-wall-maps.aspx they have a big selection of different ones.