I applaud you for your SCSI quest.  Back in 2000 I had a dual Athlon system with multiple SCSI devices using two SCSI host adapters.  I really enjoyed the speed and connectivity of SCSI.  There was simply no better way to connect a ton of devices, back then.

I had an Adaptec 2940 host bus adapter (8-bit parallel data bus with 10MHz clock) for my basic SCSI devices. -- IoMega ZIP drive, IoMega Jaz drive, CD ROM, scanner and I think a CD RW.  

The other HBA was an Adaptec 2940UW ("ultra wide", 16-bit parallel bus with 20MHz clock), to which I connected several HDDs. 

Setting up unique SCSI IDs for each device is not hard, just changing a few jumpers on each device. 

Setting up proper termination (essentially you need bus termination at each end of the cable) can be a bit tricky.