What is a good HFS+ NAS or network HDD
So, HFS+ is a closed, proprietary format. For linux to work with this format, it needs hfsprogs, which is a module that supports HFS+.

Most NAS servers use linux-native formats, so if you want HFS+-based filesystems, there are a few ways.

a) Most NAS servers are built with Linux, and most of them have command line. You can load hfsprogs module and write a script to have the system mount your HFS+ formatted drives. In another word, customize the system.

b) Roll your own server, a good Synology enclosure costs about the same price as an Mac mini, you can get an external hard drive and have it running as an server.