Manufacturers include IBM, 3M, Verbatum, and others. Drive cabinets are priced as below and may be available, ask for availability. At the moment I'm busy with support efforts, including a manuals service and my Mac business, so availability of tested drives and cabinets is limited. This may change if customer interest dictates, so I appreciate encouragments. Any working drive sold is tested for read, write, seek but not adjusted for alignment.
Supplies are obviously limited.
Documentation for drives is at extra cost, see below. Cabinets and power supplies for drives are described below. You should confirm your power supply connectors will mate with whatever drive you get. Also, watch for drive model numbers and model variations. For instance, the Shugart 800 vs the 801 is only a matter of some jumper changes.