I recently did an ECU change on my ABF. I searched high and low for a non-immobilised ECU and finally found one in, of all places, Puerto Rico!
Cost me about 175 squid to get it sent over.
Rocking horse sh!t to find, but the part no. was 037 906 024 ab.
The 'ab' revision is the one you would have to look for if you want non-imm.