I just ordered one of these, says it's new but doesn't come with any drive trays. I've seen other sellers say they have a STL for download to 3d print trays, if I can't find that I'll try making my own.
$199 + ship, he's got 26 left: SuperMicro Chenbro NR40700 4U 48-Bay Storage Chassis w/Rails & PSupplies - NEW! | eBay
$199 + ship, he's got 26 left: SuperMicro Chenbro NR40700 4U 48-Bay Storage Chassis w/Rails & PSupplies - NEW! | eBay