I purchased a NVR4216 off ebay for $100. It fits 4HDD so should work fine. The firmware is English only and a bit dated. I've tried half the firmware files on Firmwares without success. It's not a major loss if I can't upgrade, but figured I'd try before configuring the unit.
Device Type:NVR-P16-4VA
Record Channel:16
Alarm In:16
Alarm Out:4
Web Version:3.2.3.98477
Onvif Version:2.4.1
System Version:3.216.0000000.0, Build Date: 2018-06-05
Device Type:NVR-P16-4VA
Record Channel:16
Alarm In:16
Alarm Out:4
Web Version:3.2.3.98477
Onvif Version:2.4.1
System Version:3.216.0000000.0, Build Date: 2018-06-05