Doesn't the 1581 use a standard Amiga drive mechanism?
If that being the case, perhaps a drive from an a1500/a2000 would provide a good result - the drive could then be housed in one of the towers 3.5" slots and freeing up a 5 1/4" slot for some other use.......
Also, modifying a standard PC drive for use with Amiga - lots of info elsewhere on this site - might also work and save yourself a lot of time and effort?
