I just assume that you have read Marc van Eijk's well described blog post about the new enhancement with Update Rollup 5 for SCVMM, where we can now effectively turn off differential disks for all our new VM Role deployments with Azure Pack.
If not, follow this link to get all the details: http://www.hyper-v.nu/archives/mvaneijk/2015/02/windows-azure-pack-vm-role-choose-between-differencing-disks-or-dedicated-disks/
As a result of this going public, I have uploaded a new version of my SCVMM Fabric Controller script, that now will add another custom property to all the IaaS Clouds in SCVMM, assuming you want static disks to be default.
You can grab the new version from here:
Next, I will make this script a bit more user friendly and add some more functionality to it in the next couple of weeks.