Possible Clues:

• Undeveloped land surrounding a city
• Is this why The House isn't sitting there? Sounds like a dig from the environmentalists!
• Welcome must include note -- the Spanish land outside city
• Judoist's achievement that can't be built on, we were told
• A level of combat proficiency that can't be built on
• What's worn by some sporting combatants in ring for protection
• US commando having left instead of 2nd Engineers in recognition of fighting?
• Designated zone around town or city, preserved from development