lotsofdrives, Depending on your NAS devices, you could potentially use them as iSCSI targets. Present the iSCSI volumes to your windows box that has the "local" drives in it. Then pool them there. The caveat is that being remote iSCSI volumes, DrivePool and its relative software products won't be able to read any hardware data from the disks as they are not local disks.
I am doing something similar and using iSCSI to present disks to other machines where I can pool them there.