"I’ve done a quick eval and it looks like Fab3000 might work for us. One thing I haven’t been able to do is create a fillet between a trace and a pad. Is this possible, or not part of the tool suite?"
To create a fillet between the Pad and Trace could also be what FAB 3000 calls "Teardrop" (menu: Fabrication / Teardrop Creation...). Here's a video tutorial showing me create fillets between selected pad/traces. https://numericalsoftware-update.s3.amazonaws.com/tutorials/2019-05-23_11-44-17-teardrop.mp4
Here's another related link for teardrops.
Thanks again, and please let me know if you have any further questions.