Wow. Do you have any pointers to this information?
You can get easily 2GB with a SBC for less than $60.
The expensive part is the case, and power supply.
You can google it as there should be plenty of discussions. Even on HN using 1GB of memory for ZFS. [1] The two ZFS memory intensive feature is ARC ( Cache ) and De-Duplication.
The 2nd thing is that you are not using the NAS / DAS frequently in this scenario. The memory only get you extra performance. The only reason why you want ZFS is file integrity.
