Uh, now that Pyspades can make the intels appear where-ever-the-hell you want them to, how about a map like this:
Low, flat map with a small (like 5x5) platform made of god-blocks in the sky. BOTH intels spawn up there, and the teams have to build a giant tower to reach it. Since the platform is so small, BOTH teams have to build in the same spot. Naturally the tower will be a structure you'd want to defend, so you'd build an ever-growing cancer-like fortress in order to reach the intel.
It'd be called the Tower Of Babel map, because well, that's what the Tower of Babel was in the Bible.
Anyone have any suggestions on how to get an indestructible platform like that without turning off block destruction completely?