I have to ask, would there be any significant difference in weight if the leo's are up gunned to the L55's? concerning the fact that the only thing that seems to be holding back the MinDef towards the A6 or A7's is the weight issue...
According to publicly available specs, the difference of A6 to A5 in combat weight is around 3 ton. A6 and A5 differences mostly on L55 gun in A6 and L44 gun A5, however the Armour more or less similar. In other hand there are also differences on several other area, thus in my opinion those 3 ton differences is not merely the differences of L55 with L44 alone. However the differences of the gun weight seems account significant portion of the differences.
Mindef did not take on A6 or A7 not because of the difference of weight (which relatively did not make much differences), but more to
budget. The budget that being approved (after long lobby with parliament) is USD 260-280 mio range. For that budget, Mindef already promissed Parliament they can get 100 Leopard 2 MBT.
Now, the 100 Leo 2 A6 from Dutch, is one time deal. In such, the Dutch want to release their relatively new Leo 2 A6 on that price, due to their internal budgetary concern at this moment. In reality USD 270 mio budget, can't get 100 Leo 2 A6. Since Mindef found trouble diplomatically with Dutch Parliament in securing the deal, while in the same time they need to produce the contract this year if they want all of the Tanks to be operationally available by 2014, then they have to go somewhere else.
Germany can give 100+ Leo 2 with that kind of budget, but off course not with A6 and A7 specs. So that's it. It's not a weight concern. It's a budgetary concern.