So, I think I know the answer to this (do it the long way) but i wanted to run it by the community just in case I was wrong.
The Environment:
vSphere 5 Enterprise
ESXi 5.1.0.
vm: Windows serer 2008 standard (not R2).
upgrading to a 2012R2 server.
Originally, there were never any LUNs/datastores made over 500GB because of the old-school cluster sizing before VMFS5.
Basically, we had a 225GB drive on a Windows file server. More space was needed, so rather than increasing the size of the virtual disk, and expanding it in windows, they added another 225GB disk to the vm, from a different datastore, and spanned the disks in Windows. This was performed again later, so this vm currently has three separate 225GB disks (four if you count the system disk) on three separate datastores, that the OS sees as a single 675GB drive.
What I would LIKE to do is simply merge those three vmdk's via magic into a single VMDK, then just mount that VMDK onto the new server. I've read some documentation and some posts here and there regarding merging split vmdks into monolithic ones, but that's still VMware presenting the OS with a single disk that happens to be broken up into pieces, and not VMware presenting the OS with multiple disks that the OS itself combines into one piece.
I'm 90% sure that this is just a pipe dream, but it (usually) never hurts to ask if anyone has run across a similar experience.
Thanks!