I have tried to gather this information straight from the horse's mouth without success so here we go:
Does the KPC K45 support SATA Multipliers?
Considering the price point, it would be fairly nice to match this with some additional ram, a flash boot drive with FreeNAS, an e-SATA multiplier such as the AMS Venus T5 (or two) and a few drives.
If there is hardware support however the software has not caught up I could just run FreeNAS over VMWare.
"The eSATA Port Multiplier requires an eSATA port with a controller that is AHCI compliant (Advanced Host Controller Interface). This requirement disqualifies all integrated controllers that are two or three years old (ICH7 and older)"
Too bad I did not manage to come up with the right search keyword.