http://amigakit.leamancomputing.com/catalog/product_info.php?cPath=39&products_id=1164
This would be nice if it were for the 3000T, unfortunately the 3000 desktop PSU has a different connector.
I ended up wiring up an AT PSU (fit nicely inside the original 3000T PSU's case) using the pinout in the previous post and it worked fine.
edit: I could be mistaken (it's been a couple of years,) but I believe the actual connector on the 3000T board is the same used for 24-pin ATX power supplies. I seem to recall buying a brand new harness to use instead of cutting the old one off of the original PSU.