Like DIY, just the enclosure, or the whole kit and kaboodle?

In any event, I've used Synology and QNAP products for over a decade and both are solid. I've also built my own by just building a server in a full tower case and putting 8+ HDs in it.

It really depends on your needs and wants, but if you start looking through the two brands above, I'm sure you'll find something that fits your criteria.