This was talked about a some weeks ago, and yes, that is possible with a third-party System Industries controller type 3040. This comes as a separate 19" box.

Some documents :

The System Industries 3040 controller ( and Omnibus interface to it ) is fully described here :
ftp://ftp.dreesen.ch/ftp/DRI/SI3040_Controller.pdf

The DRI400 Series Diskdrives ( seem to be identical to Diablo-44 ) is shown here :
ftp://ftp.dreesen.ch/ftp/DRI/DRI_4000_Series.pdf

The OS8 driver for this combo can be downloaded from Willem van der Mark's website :
http://www.vandermark.ch/pdp8/index.php

He is the original author of this driver.

Finding an actual controller is of course the difficult part...

Jos