I have been updating my VMDK using winimage as new releases come out. You can just replace the bzimage, bzroot, and the new bzroot-gui files in your VMDK each time there is a new release. I can post mine after each update if there is interest.
Edit: Here are my VMDKs for 6.1.9 and 6.2.
unRAIDServer-x86_64_v_6_1_9
unRAIDServer-x86_64_v_6_2