PLA warps over time even at low heat. that said, as long as you have good airflow it shouldn’t be a problem to use it for housing, but anything directly contacting the drives might warp.

I thought about doing this myself and was leaning towards reusing drive sleds from existing hardware. it’ll save on design and printing time as well as alleviate problems with heat and the printed parts.

the sleds are usually pretty cheap on ebay, and you can always buy replacements without much effort.