Here is another stopgap project - this time an experiment in more complex and intricate designs.

Firstly, credit where credit is due!:
Design credit for the exterior appearance of the turret goes to Ansel Hsiao, designer of epic Star Destroyers - so epic that they became canon; his website is here http://fractalsponge.net
This creation makes use of the wonderful Space Architect resource pack by [url=www.planetminecraft.com/member/scamper3396/ ]Scamper3396[/url], check it out here: http://www.planetminecraft.com/texture_pack/space-architect-v001 (this model will look a mess without it)
(also, this pack is a slightly modified version of scamper's original pack.)

Some information:

The turret shown is a quad barrelled, (likely) remotely controlled heavy turbolaser turret. It is roughly 17m wide and 23m long including gun barrels, and a 1:1 scale representation of the turret as found on the Allegiance-class Heavy Star Destroyer (ASD). Twelve of these turrets serve as the primary broadside armament of the ASD. They are rated at ~175 teraton maximum firepower output (per barrel (I think it is per barrel anyway)), which accounts for a hefty requirement from the ASD's ~218m diameter primary hypermatter-annihilation reactor.

It is one of the many descendants of the venerated Venator-class' DBY-827 Heavy Dual Turbolaser Turrets, and is the ASD's counterpart to the Imperial I-class Star Destroyer's 'Heavy Turbolaser Turret' (which is dual-barrelled.) If it is anything like the ISD-I's turrets, it is a remotely controlled behemoth.

Included in this model is an interior which reflects the maintenance access and direct systems interface aspects of the turret, as well as a manual control room for aiming and firing the gun, as well as rudimentary power management and fire control interfaces.

The design (as it stands; as a prototype) encompasses

• Two main capacitors - each providing power to a fire-linked pair of guns, providing enough output for a single shot or burst, while the main capacitors would sit well within the hull of the ship's hull itself - with power on/off switches,
  
• 4 gun barrels in two fire-linked pairs, each of which can be armed or disarmed manually at the forward area of the turret's interior.
  
• Azimuth and Elevation manual overrides and maintenance stations.
  
• There are also a plethora of conduits; providing the power for the capacitors (which then unload directly into the gun), as well as accomodating for a cooling loop and providing power to the elevation mechanisms of the gun.
  
• Finally, there are a few vents and other cooling systems, as well as relevant control surfaces and maintenance accessways for granting ship crew or droids access to critical systems if direct input is needed.
  

There are some flaws present in this model, namely - 
- Lack of structural bracing and overall support and framework
- Slight mismatch in appearance in this creation and actual appearance of the design; due to oversight
- Lack of accomodation for tibanna-gas based mechanics (if applicable)
- Design not optimised (messay cable management etc., lol)
- Lack of remote mechanisms
I may address these in future releases. (unlikely though)

Do whatever you like with this, just give credit where credit's due.