Ask around on LEMswap, somebody maybe a week or two ago was giving away a copy for classic mac (v4 maybe?).

I have retrospect for A/UX and V2.x for 68 mac (think it works with PPC as well).

The issues you will have is the software needs a driver for the model DAT you are going to use, I have no problem with SONY DDS2 models on 68k macs but I have not tried the DDS3 and DDS4 units with it.