This is a map I spent a while doing, my mates seemed to like it, so I've decided to enter it into the Forgetacular contest, and show ForgeHub.
It has a central tower, along with 4 towers on the cardinal points and a vehicular bottom layer. It works with everything except Race, Rally, Conquest, 3-Plots (I think), Rocket Race and Invasion (Slayer).

Pics (caption below image):

Overview

Overview 2

Base x4 at Cardinal Points

Base Ground Floor (Plasma Pistol, DMR, Assault Rifle, Assault Bomb)

Base 1st Floor (Flag, Assault Goal etc.)

Base 1st Floor to Roof Stairway + Roof (Magnum, 2x Frag Grenade)

Central Tower (Ghost + Mongoose)

Central Tower Ground Floor (2x DMR, 2x Health Station, Neutral Bomb, Neutral Flag etc.)

Central Tower 1st Floor (Plasma Launcher) Green + Orange Connections

Central Tower 2nd Floor (Shotgun, Plasma Repeater, 2x Health Station) Red + Blue Connections

Central Tower Roof (Assault Rifle, Focus Rifle, Grenade Launcer, Plasma Pistol)

Blue to Orange Bridge Ramp (Rocket Launcher, 2x Plasma Grenade)

Red to Green Bridge Ramp (Gravity Hammer, 2x Plasma Grenade)

Blue to Green Bridge (Warthog, 2x Plasma Grenade)

Red to Orange Bridge (Revenant, 2x Plasma Grenade)

Green/Orange to Central Tower Bridge (DMR/Needle Rifle)

Red/Blue to Central Tower Bridge (Assault Rifle/Needler)

Totals:
1x Mongoose
1x Ghost
1x Revenant
1x Gauss Warthog
7x DMR
4x Magnum
6x Assault Rifle
1x Shotgun
1x Needler
1x Needle Rifle
1x Plasma Repeater
1x Focus Rifle
5x Plasma Pistol
1x Rocket Launcher
1x Gravity Hammer
1x Grenade Launcher
8x Plasma Grenade
8x Frag Grenade

Finally, thanks to DecidingHawk for help placing some weapons and spawns.
Thanks to Kamikaze Lynx, strike at night, elite inforcer, DecidingHawk, Kamikaze Guitar, DUKEHOUSE, EliteMaster030 and 4 others (can't remember off the top of my head) for testing. Please give constructive criticism!

Changed for the next Update:
Shades re-added
Wildly reworked weaponry.

Make sure you review that list before suggesting something.