Note: I've updated the legenda, I mixed up the colors for 'no longer in use' and 'no MBT version'.
Leopard II A0 to A3:
The first production batches are called A0 to A3. The changes between the different models are minimal and mainly involve internal upgrades like better fuelfilters and radio's. The difference on the outside are minimal. All A0 versions are upgrated to the A1 version, then to the A2 version, then to the A3 versions and finally to the A4 versions. Hasegawa makes a model with a slighty different attenna as used on the A4 versions. If I remember correctly this antenna was used on the A0 to A2 versions if I remember correctly. (I couldn't find the part where I read it)
Leopard II A4:
The leopard II A4 can be seen as the last version as it was used in the late 80's and early nighties. The difference on the outside with the A0 to A3 version is minimal, actually just a small hatch in the newer production vehicles. As said all leopard tanks are upgraded to this standard. This model of the Leopard II is the most used and exported version. It is used for example by Poland, Turkey, Finland, Austria and Chilli. Dragon and Revell (no. 03103) make of model of this version in 1/72. The Hasegawa Leopard can also be used since the difference is only an antenna.
Leopard II A5:
The difference between the Leopard II A4 and A5 is big on the outside and thus of interest for modellers. The largest difference is the addition of a wedged shaped piece of armour to the turret. Newer electronics all also added on the inside of the tank. Revell makes at least one model of this version as product no.03105. Maybe the new A5NL model is a A5 version as advertised but I'm not sure.
Leopard II A6/A6M:
The Leopard II A6 differences from the A5 version by the L55 gun which has a barrel that is 1,3m longer as the L44 gun from the leopard A0 to A5. The A6M version is a version of the leopard with an extra armoured underside to protect the crew against mines. This modification is an addaption to the situation in Afganistan. Revell no.03180 is a model which can be build as both versions.
Leopard II A4 Revolution:
The Leopard II A4 Revolution is an A4 model upgraded to meet the demands of the new century. It features better electronics and a allround armour upgrade changing it's appearence considerably. Singapoure uses this version of the Leopard.
Leopard II A6E:
Leopard II A6E is short for Leopard II 'Espania'. This version of the leopard is not only used by Spain but also by Greece and Sweden where they are called 'HEL' and 'StrV. 122' respectively. The main difference on the outside with the A5 and A6 version is the extra armor and headlights. Unfortunately there is no model of this version in 1/72.
Tanks are originally developed as support for the infantry in WWI effectively repleacing the horse based cavalry which had that task for centuries before in European armies. (In other parts of the world cavalry had a more independend role) Horses where not just used in the cavalry but also to support armies by transporting guns and wounded. The tank follows this patern and different versions are made for other purposes as shooting down the enemy. Of the Leopard II there are six different 'support' versions.
Driver training vehicle
The name of this version explains preciesely what it does, training the driver to drive the tank.
Buffalo recovery vehicle
A tank can have engine failure or get stuck in in the mud. A lagere power source is needed to get the compromised vehicle out of trouble. Usually this is done by an other tank especially modified for this purpose known as 'Armored Recovery Vehicle'. The Buffalo is the ARV-version of the Leopard II and features a dozerblade, crane and machinegun for it's defence.
Kodiak Combat Engineering Vehicle
Sometimes it is needed to dig a large hole, get obstacles out of the way or build a command center in rough terrain far from the civilized world or in a devastaded city. For this pupose Combat Engineering Vehicles (CEV's) are used. The Leopard II CEV is known as Kodiak. A prominent feature of the Kodiak is it's large excavator. The dutch version will also be able to clear minefields.
Tanks are able to wade through deep water. With the right equipment a leopard can even 'dive' dissapearing completely under water. The tanks have to be specially prepared for this however, other vehicles can't do this and it can be done to cross rivers with steep edges. Laying a potoon bridge is an alternative way to cross a river but a third option is using a 'fast bridge'. There are two versions of the leopard II capable of laying a bridge in recordtime: The 'Leopard II Fast bridge' made by MAN and the 'Leopard II LEGUAN' made by Patria for the Finnish army.
A classical task of the tank is clearing mines. The leopard IIR is a minesweeper made by Patria for the Finnish army and is the version of the Leopard II dedicated to sweeping mines. The Dutch version of the Kodiak can also be used for this task but is capable of performing other duties as well.
Leopard II A4 140mm
During the armsrace of the cold war militairy equipment was continually improved. For the Leopard II this was no difference and she was tested with a 140mm gun. Tests where succesfull but it was decided to keep the 120mm gun since it was sufficient at the time.
Leopard II A5PSO:
The leopard II A5PSO (Peace Support Operations) is a prototype of a leopard version optimized for urban warfare. It features allround protection, a short barrel, secondiary weapon system, dozerblade and better sensors.
Leopard II A7+
The Leopard II A7+ is the newest version of the Leopard II designed as an allround battle tank. The most prominent changes with it's predecesors are the improved armour and a machinegun that van be controled from the inside of the turret.
With 10 MBT versions, 6 support versions and 3 prototypes the leopard II family is quite extended. Some versions in the family tree are almost identical on the outside. Fact is that this family tree is not complete yet. Every country has it's own 'style' of Leopard II. The differences between smoke granate launchers are largre for example and there is also a large variantion in side skirts. These differences or minor however. A somewhat lager difference will be formed by the Leopard II A4's of the Chilean army because these will be fitted whit the L55 long barreled gun as used in the A6 version. The leopard II's used in Afganistan by Canada and Denmark are also fitted with bararmor to protect them against hollowpoint charges. The result is that the Leopard II complete family three looks like the family tree of the real leopard (the animal). This is a reflection that, just like in nature, weapon development is a proces of small steps improving to addapt to the latest challenges put up by the environment.
The basic A4, A5 and A6 version are made as a 1/72 model. To make other versions one has to modify these models or maybe buy a resin version. More about a few models of Leopard II's van be read on this weblog, more on the Leopard II tank itself on here wikipedia.